Try-with-Resources

⋯3public class MultipleResources {4    public static void main(String[] args) {5        System.out.println("=== Multiple Resources ===\n");67        // Multiple resources - closed in reverse order //?multiple_basic8        System.out.println("--- Multiple Resources (Reverse Close Order) ---");⋯

⋯83public Resource(String namefirst) { //?resource_constructor84    this.name→ first = namefirst;85    System.out.println("  → Opening: " + namefirst); //?print_opening86}⋯

⋯10try ( //?try_multiple11    Resource r1⟨Resource A⟩ = new Resource("first");   //?resource112    Resource r2⟨Resource B⟩ = new Resource("second");  //?resource213    Resource r3⟨Resource C⟩ = new Resource("third")    //?resource314) { //?multiple_body15    System.out.println("Using all resources..."); //?using_all16    r1.use(); //?use_r117    r2.use(); //?use_r2⋯

⋯15            System.out.println("Using all resources..."); //?using_all16            r1.use(); //?use_r117            r2.use(); //?use_r218            r3.use(); //?use_r319        }2021        System.out.println(); //?newline2223        // Chained resources //?chained24        System.out.println("--- Chained Resources ---");2526        try ( //?try_chained27            OuterResource outer = new OuterResource("outer"); //?outer28            InnerResource inner = new InnerResource("inner", outer) //?inner29        ) {30            inner.process(); //?process_inner31        }3233        System.out.println(); //?newline23435        // One resource fails to open //?fail_to_open36        System.out.println("--- When Opening Fails ---");3738        try ( //?try_fail_open39            Resource r1 = new Resource("good1"); //?good140            Resource r2 = new FailingResource("failing"); //?failing41            Resource r3 = new Resource("good2") //?good2_never42        ) {43            System.out.println("This won't execute"); //?wont_execute44        } catch (RuntimeException e) { //?catch_fail_open45            System.out.println("Caught: " + e.getMessage()); //?print_fail_open46        }4748        System.out.println("\nNotice: Only successfully opened resources are closed."); //?notice4950        System.out.println(); //?newline35152        // Exception during use //?exception_during_use53        System.out.println("--- Exception During Use ---");5455        try ( //?try_exception_use56            Resource r1 = new Resource("A"); //?res_a57            Resource r2 = new Resource("B"); //?res_b58            Resource r3 = new Resource("C")  //?res_c59        ) {60            r1.use(); //?use_a61            throw new RuntimeException("Error during processing"); //?throw_during62        } catch (RuntimeException e) { //?catch_during63            System.out.println("Caught: " + e.getMessage()); //?print_during64        }6566        System.out.println("All resources were closed despite the exception."); //?all_closed6768        System.out.println("\n=== Key Points ===");69        System.out.println("""70            1. Declare multiple resources separated by semicolons71            2. Resources closed in REVERSE order (LIFO)72            3. If opening fails, previously opened resources are closed73            4. All resources closed even if exception in try body74            5. Useful for dependent resources (e.g., BufferedReader wraps FileReader)75            """);76    }77}7879// Basic resource //?resource_class80class Resource implements AutoCloseable { //?resource_def81    protected final String name; //?resource_name8283    public Resource(String name) { //?resource_constructor84        this.name = name;85        System.out.println("  → Opening: " + name); //?print_opening86    }8788    public void use() { //?use_method89        System.out.println("    Using: " + namefirst); //?print_using90    }⋯

⋯92@Override93public void close() { //?close_resource94    System.out.println("  ← Closing: " + namethird); //?print_closing95}⋯

⋯110public OuterResource(String nameouter) { //?outer_constructor111    this.name→ outer = nameouter;112    System.out.println("  → Opening outer: " + nameouter); //?print_outer_open113}⋯

⋯130public InnerResource(String nameinner, OuterResource outer⟨OuterResource D⟩) { //?inner_constructor131    this.name→ inner = nameinner;132    this.outer→ ⟨OuterResource D⟩ = outer⟨OuterResource D⟩;133    System.out.println("  → Opening inner: " + nameinner + " (wraps " + outer.getData() + ")"); //?print_inner_open134}⋯

⋯115public String getData() { //?get_data116    return "data from " + nameouter; //?return_data117}⋯

⋯132    this.outer = outer;133    System.out.println("  → Opening inner: " + nameinner + " (wraps " + outer.getData() + ")"); //?print_inner_open134}⋯

⋯26try ( //?try_chained27    OuterResource outer⟨OuterResource D⟩ = new OuterResource("outer"); //?outer28    InnerResource inner⟨InnerResource H⟩ = new InnerResource("inner", outer) //?inner29) {30    inner.process(); //?process_inner31}⋯

⋯115public String getData() { //?get_data116    return "data from " + nameouter; //?return_data117}⋯

⋯29        ) {30            inner.process(); //?process_inner31        }3233        System.out.println(); //?newline23435        // One resource fails to open //?fail_to_open36        System.out.println("--- When Opening Fails ---");3738        try ( //?try_fail_open39            Resource r1 = new Resource("good1"); //?good140            Resource r2 = new FailingResource("failing"); //?failing41            Resource r3 = new Resource("good2") //?good2_never42        ) {43            System.out.println("This won't execute"); //?wont_execute44        } catch (RuntimeException e) { //?catch_fail_open45            System.out.println("Caught: " + e.getMessage()); //?print_fail_open46        }4748        System.out.println("\nNotice: Only successfully opened resources are closed."); //?notice4950        System.out.println(); //?newline35152        // Exception during use //?exception_during_use53        System.out.println("--- Exception During Use ---");5455        try ( //?try_exception_use56            Resource r1 = new Resource("A"); //?res_a57            Resource r2 = new Resource("B"); //?res_b58            Resource r3 = new Resource("C")  //?res_c59        ) {60            r1.use(); //?use_a61            throw new RuntimeException("Error during processing"); //?throw_during62        } catch (RuntimeException e) { //?catch_during63            System.out.println("Caught: " + e.getMessage()); //?print_during64        }6566        System.out.println("All resources were closed despite the exception."); //?all_closed6768        System.out.println("\n=== Key Points ===");69        System.out.println("""70            1. Declare multiple resources separated by semicolons71            2. Resources closed in REVERSE order (LIFO)72            3. If opening fails, previously opened resources are closed73            4. All resources closed even if exception in try body74            5. Useful for dependent resources (e.g., BufferedReader wraps FileReader)75            """);76    }77}7879// Basic resource //?resource_class80class Resource implements AutoCloseable { //?resource_def81    protected final String name; //?resource_name8283    public Resource(String name) { //?resource_constructor84        this.name = name;85        System.out.println("  → Opening: " + name); //?print_opening86    }8788    public void use() { //?use_method89        System.out.println("    Using: " + name); //?print_using90    }9192    @Override93    public void close() { //?close_resource94        System.out.println("  ← Closing: " + name); //?print_closing95    }96}9798// Resource that fails during construction //?failing_resource_class99class FailingResource extends Resource { //?failing_resource_def100    public FailingResource(String name) { //?failing_constructor101        super(name); //?super_call102        throw new RuntimeException("Failed to open: " + name); //?throw_fail103    }104}105106// Outer resource //?outer_resource_class107class OuterResource implements AutoCloseable { //?outer_def108    private final String name; //?outer_name109110    public OuterResource(String name) { //?outer_constructor111        this.name = name;112        System.out.println("  → Opening outer: " + name); //?print_outer_open113    }114115    public String getData() { //?get_data116        return "data from " + name; //?return_data117    }118119    @Override120    public void close() { //?close_outer121        System.out.println("  ← Closing outer: " + name); //?print_outer_close122    }123}124125// Inner resource that depends on outer //?inner_resource_class126class InnerResource implements AutoCloseable { //?inner_def127    private final String name; //?inner_name128    private final OuterResource outer; //?outer_ref129130    public InnerResource(String name, OuterResource outer) { //?inner_constructor131        this.name = name;132        this.outer = outer;133        System.out.println("  → Opening inner: " + name + " (wraps " + outer.getData() + ")"); //?print_inner_open134    }135136    public void process() { //?process_method137        System.out.println("    Processing with " + outer.getData()); //?print_process138    }⋯

⋯140@Override141public void close() { //?close_inner142    System.out.println("  ← Closing inner: " + nameinner); //?print_inner_close143}⋯

⋯33        System.out.println(); //?newline23435        // One resource fails to open //?fail_to_open36        System.out.println("--- When Opening Fails ---");3738        try ( //?try_fail_open39            Resource r1 = new Resource("good1"); //?good140            Resource r2 = new FailingResource("failing"); //?failing41            Resource r3 = new Resource("good2") //?good2_never42        ) {43            System.out.println("This won't execute"); //?wont_execute44        } catch (RuntimeException e) { //?catch_fail_open45            System.out.println("Caught: " + e.getMessage()); //?print_fail_open46        }4748        System.out.println("\nNotice: Only successfully opened resources are closed."); //?notice4950        System.out.println(); //?newline35152        // Exception during use //?exception_during_use53        System.out.println("--- Exception During Use ---");5455        try ( //?try_exception_use56            Resource r1 = new Resource("A"); //?res_a57            Resource r2 = new Resource("B"); //?res_b58            Resource r3 = new Resource("C")  //?res_c59        ) {60            r1.use(); //?use_a61            throw new RuntimeException("Error during processing"); //?throw_during62        } catch (RuntimeException e) { //?catch_during63            System.out.println("Caught: " + e.getMessage()); //?print_during64        }6566        System.out.println("All resources were closed despite the exception."); //?all_closed6768        System.out.println("\n=== Key Points ===");69        System.out.println("""70            1. Declare multiple resources separated by semicolons71            2. Resources closed in REVERSE order (LIFO)72            3. If opening fails, previously opened resources are closed73            4. All resources closed even if exception in try body74            5. Useful for dependent resources (e.g., BufferedReader wraps FileReader)75            """);76    }77}7879// Basic resource //?resource_class80class Resource implements AutoCloseable { //?resource_def81    protected final String name; //?resource_name8283    public Resource(String name) { //?resource_constructor84        this.name = name;85        System.out.println("  → Opening: " + name); //?print_opening86    }8788    public void use() { //?use_method89        System.out.println("    Using: " + name); //?print_using90    }9192    @Override93    public void close() { //?close_resource94        System.out.println("  ← Closing: " + name); //?print_closing95    }96}9798// Resource that fails during construction //?failing_resource_class99class FailingResource extends Resource { //?failing_resource_def100    public FailingResource(String name) { //?failing_constructor101        super(name); //?super_call102        throw new RuntimeException("Failed to open: " + name); //?throw_fail103    }104}105106// Outer resource //?outer_resource_class107class OuterResource implements AutoCloseable { //?outer_def108    private final String name; //?outer_name109110    public OuterResource(String name) { //?outer_constructor111        this.name = name;112        System.out.println("  → Opening outer: " + name); //?print_outer_open113    }114115    public String getData() { //?get_data116        return "data from " + name; //?return_data117    }118119    @Override120    public void close() { //?close_outer121        System.out.println("  ← Closing outer: " + nameouter); //?print_outer_close122    }⋯

⋯99class FailingResource extends Resource { //?failing_resource_def100    public FailingResource(String namefailing) { //?failing_constructor101        super(name); //?super_call102        throw new RuntimeException("Failed to open: " + name); //?throw_fail103    }⋯

⋯43    System.out.println("This won't execute"); //?wont_execute44} catch (RuntimeException ejava.lang.RuntimeException: Failed to open: failing) { //?catch_fail_open45    System.out.println("Caught: " + e.getMessage()); //?print_fail_open46}⋯

⋯48System.out.println("\nNotice: Only successfully opened resources are closed."); //?notice4950System.out.println(); //?newline35152// Exception during use //?exception_during_use53System.out.println("--- Exception During Use ---");⋯

⋯55try ( //?try_exception_use56    Resource r1⟨Resource E⟩ = new Resource("A"); //?res_a57    Resource r2⟨Resource F⟩ = new Resource("B"); //?res_b58    Resource r3⟨Resource G⟩ = new Resource("C")  //?res_c59) {60    r1.use(); //?use_a61    throw new RuntimeException("Error during processing"); //?throw_during⋯

⋯61    throw new RuntimeException("Error during processing"); //?throw_during62} catch (RuntimeException ejava.lang.RuntimeException: Error during processing) { //?catch_during63    System.out.println("Caught: " + e.getMessage()); //?print_during64}⋯

⋯66    System.out.println("All resources were closed despite the exception."); //?all_closed6768    System.out.println("\n=== Key Points ===");69    System.out.println("""70        1. Declare multiple resources separated by semicolons71        2. Resources closed in REVERSE order (LIFO)72        3. If opening fails, previously opened resources are closed73        4. All resources closed even if exception in try body74        5. Useful for dependent resources (e.g., BufferedReader wraps FileReader)75        """);76}⋯

⋯3public class CustomAutocloseable {4    public static void main(String[] args) {5        System.out.println("=== Custom AutoCloseable Classes ===\n");67        // Basic custom resource //?basic_custom8        System.out.println("--- Basic Custom Resource ---");⋯

⋯66public Timer(String operationNameoperation) { //?timer_constructor67    this.operationName→ operation = operationNameoperation;68    System.out.println("  [Timer] Started: " + operationNameoperation); //?print_started69}⋯

⋯10try (Timer timer⟨Timer A⟩ = new Timer("operation")) { //?try_timer11    timer.simulateWork(100); //?simulate_work12    System.out.println("  Operation completed"); //?completed⋯

⋯10        try (Timer timer = new Timer("operation")) { //?try_timer11            timer.simulateWork(100); //?simulate_work12            System.out.println("  Operation completed"); //?completed13        }1415        // Resource with state //?stateful16        System.out.println("\n--- Stateful Resource ---");1718        try (Counter counter = new Counter()) { //?try_counter19            counter.increment(); //?inc120            counter.increment(); //?inc221            counter.increment(); //?inc322            System.out.println("  Count: " + counter.getCount()); //?print_count23        }2425        // Resource that can fail on close //?fail_on_close26        System.out.println("\n--- Resource That May Fail on Close ---");2728        try (SafeResource resource = new SafeResource()) { //?try_safe29            resource.process(); //?process_safe30        }3132        // Idempotent close //?idempotent33        System.out.println("\n--- Idempotent Close ---");3435        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis100) { //?simulate_work_method72        elapsedMs→ 100 += millis100; //?add_elapsed73    }⋯

⋯15        // Resource with state //?stateful16        System.out.println("\n--- Stateful Resource ---");1718        try (Counter counter = new Counter()) { //?try_counter19            counter.increment(); //?inc120            counter.increment(); //?inc221            counter.increment(); //?inc322            System.out.println("  Count: " + counter.getCount()); //?print_count23        }2425        // Resource that can fail on close //?fail_on_close26        System.out.println("\n--- Resource That May Fail on Close ---");2728        try (SafeResource resource = new SafeResource()) { //?try_safe29            resource.process(); //?process_safe30        }3132        // Idempotent close //?idempotent33        System.out.println("\n--- Idempotent Close ---");3435        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationNameoperation + " took " + elapsedMs100 + "ms"); //?print_elapsed78    }⋯

⋯18try (Counter counter⟨Counter B⟩ = new Counter()) { //?try_counter19    counter.increment(); //?inc120    counter.increment(); //?inc2⋯

⋯18        try (Counter counter = new Counter()) { //?try_counter19            counter.increment(); //?inc120            counter.increment(); //?inc221            counter.increment(); //?inc322            System.out.println("  Count: " + counter.getCount()); //?print_count23        }2425        // Resource that can fail on close //?fail_on_close26        System.out.println("\n--- Resource That May Fail on Close ---");2728        try (SafeResource resource = new SafeResource()) { //?try_safe29            resource.process(); //?process_safe30        }3132        // Idempotent close //?idempotent33        System.out.println("\n--- Idempotent Close ---");3435        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count→ 1++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed⋯

⋯21    counter.increment(); //?inc322    System.out.println("  Count: " + counter.getCount()); //?print_count23}⋯

⋯25        // Resource that can fail on close //?fail_on_close26        System.out.println("\n--- Resource That May Fail on Close ---");2728        try (SafeResource resource = new SafeResource()) { //?try_safe29            resource.process(); //?process_safe30        }3132        // Idempotent close //?idempotent33        System.out.println("\n--- Idempotent Close ---");3435        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closedfalse) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count3); //?print_final106            closed→ true = true; //?set_closed107        }⋯

⋯28try (SafeResource resource⟨SafeResource C⟩ = new SafeResource()) { //?try_safe29    resource.process(); //?process_safe30}⋯

⋯28        try (SafeResource resource = new SafeResource()) { //?try_safe29            resource.process(); //?process_safe30        }3132        // Idempotent close //?idempotent33        System.out.println("\n--- Idempotent Close ---");3435        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }⋯

⋯118@Override119public void close() { //?safe_close120    System.out.println("  [SafeResource] Closing..."); //?print_closing121    try { //?try_cleanup⋯

⋯32        // Idempotent close //?idempotent33        System.out.println("\n--- Idempotent Close ---");3435        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }⋯

⋯35try (IdempotentResource resource⟨IdempotentResource D⟩ = new IdempotentResource()) { //?try_idempotent36    resource.use(); //?use_idempotent37    resource.close(); //?manual_close⋯

⋯35        try (IdempotentResource resource = new IdempotentResource()) { //?try_idempotent36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }135}136137// Resource with idempotent close //?idempotent_class138class IdempotentResource implements AutoCloseable { //?idempotent_def139    private boolean closed = false; //?idempotent_closed140    private int closeCallCount = 0; //?close_call_count141142    public void use() { //?use_method143        if (closed) throw new IllegalStateException("Already closed"); //?check_use144        System.out.println("  [Idempotent] Using resource"); //?print_using145    }⋯

⋯147@Override148public void close() { //?idempotent_close149    closeCallCount→ 1++; //?increment_count150    System.out.println("  [Idempotent] close() called (call #" + closeCallCount1 + ")"); //?print_call⋯

⋯36            resource.use(); //?use_idempotent37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }135}136137// Resource with idempotent close //?idempotent_class138class IdempotentResource implements AutoCloseable { //?idempotent_def139    private boolean closed = false; //?idempotent_closed140    private int closeCallCount = 0; //?close_call_count141142    public void use() { //?use_method143        if (closed) throw new IllegalStateException("Already closed"); //?check_use144        System.out.println("  [Idempotent] Using resource"); //?print_using145    }146147    @Override148    public void close() { //?idempotent_close149        closeCallCount++; //?increment_count150        System.out.println("  [Idempotent] close() called (call #" + closeCallCount + ")"); //?print_call151152        if (!closedfalse) { //?first_close_check153            closed→ true = true; //?do_close154            System.out.println("  [Idempotent] Actually closing resources"); //?actually_close155        } else {⋯

⋯37            resource.close(); //?manual_close38            resource.close(); //?manual_close239            // Will be called again automatically //?auto_close_comment40        }4142        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }135}136137// Resource with idempotent close //?idempotent_class138class IdempotentResource implements AutoCloseable { //?idempotent_def139    private boolean closed = false; //?idempotent_closed140    private int closeCallCount = 0; //?close_call_count141142    public void use() { //?use_method143        if (closed) throw new IllegalStateException("Already closed"); //?check_use144        System.out.println("  [Idempotent] Using resource"); //?print_using145    }146147    @Override148    public void close() { //?idempotent_close149        closeCallCount++; //?increment_count150        System.out.println("  [Idempotent] close() called (call #" + closeCallCount + ")"); //?print_call151152        if (!closed) { //?first_close_check153            closed = true; //?do_close154            System.out.println("  [Idempotent] Actually closing resources"); //?actually_close155        } else {156            System.out.println("  [Idempotent] Already closed, doing nothing"); //?already_closed157        }⋯

⋯42        // Resource with cleanup action //?cleanup_action43        System.out.println("\n--- Resource with Cleanup Callback ---");4445        try (CallbackResource resource = new CallbackResource( //?try_callback46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }135}136137// Resource with idempotent close //?idempotent_class138class IdempotentResource implements AutoCloseable { //?idempotent_def139    private boolean closed = false; //?idempotent_closed140    private int closeCallCount = 0; //?close_call_count141142    public void use() { //?use_method143        if (closed) throw new IllegalStateException("Already closed"); //?check_use144        System.out.println("  [Idempotent] Using resource"); //?print_using145    }146147    @Override148    public void close() { //?idempotent_close149        closeCallCount++; //?increment_count150        System.out.println("  [Idempotent] close() called (call #" + closeCallCount + ")"); //?print_call151152        if (!closed) { //?first_close_check153            closed = true; //?do_close154            System.out.println("  [Idempotent] Actually closing resources"); //?actually_close155        } else {156            System.out.println("  [Idempotent] Already closed, doing nothing"); //?already_closed157        }⋯

⋯165public CallbackResource(Runnable cleanupAction⟨CustomAutocloseable lambda E⟩) { //?callback_constructor166    this.cleanupAction→ ⟨CustomAutocloseable lambda E⟩ = cleanupAction⟨CustomAutocloseable lambda E⟩;167    System.out.println("  [Callback] Resource created"); //?print_created168}⋯

⋯45try (CallbackResource resource⟨CallbackResource F⟩ = new CallbackResource( //?try_callback46        () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47    resource.process(); //?process_callback48}⋯

⋯46                () -> System.out.println("  [Cleanup] Resources freed!"))) { //?callback_lambda47            resource.process(); //?process_callback48        }4950        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }135}136137// Resource with idempotent close //?idempotent_class138class IdempotentResource implements AutoCloseable { //?idempotent_def139    private boolean closed = false; //?idempotent_closed140    private int closeCallCount = 0; //?close_call_count141142    public void use() { //?use_method143        if (closed) throw new IllegalStateException("Already closed"); //?check_use144        System.out.println("  [Idempotent] Using resource"); //?print_using145    }146147    @Override148    public void close() { //?idempotent_close149        closeCallCount++; //?increment_count150        System.out.println("  [Idempotent] close() called (call #" + closeCallCount + ")"); //?print_call151152        if (!closed) { //?first_close_check153            closed = true; //?do_close154            System.out.println("  [Idempotent] Actually closing resources"); //?actually_close155        } else {156            System.out.println("  [Idempotent] Already closed, doing nothing"); //?already_closed157        }158    }159}160161// Resource with cleanup callback //?callback_class162class CallbackResource implements AutoCloseable { //?callback_def163    private final Runnable cleanupAction; //?cleanup_action_field164165    public CallbackResource(Runnable cleanupAction) { //?callback_constructor166        this.cleanupAction = cleanupAction;167        System.out.println("  [Callback] Resource created"); //?print_created168    }169170    public void process() { //?callback_process171        System.out.println("  [Callback] Processing..."); //?print_callback_process172    }⋯

⋯50        System.out.println("\n=== Key Points ===");51        System.out.println("""52            1. Implement AutoCloseable interface53            2. close() should be idempotent (safe to call multiple times)54            3. Don't throw exceptions in close() if possible55            4. Track state to prevent use after close56            5. Consider what cleanup is actually needed57            """);58    }59}6061// Timer resource - measures elapsed time //?timer_class62class Timer implements AutoCloseable { //?timer_def63    private final String operationName; //?operation_name64    private long elapsedMs = 0; //?elapsed_field6566    public Timer(String operationName) { //?timer_constructor67        this.operationName = operationName;68        System.out.println("  [Timer] Started: " + operationName); //?print_started69    }7071    public void simulateWork(long millis) { //?simulate_work_method72        elapsedMs += millis; //?add_elapsed73    }7475    @Override76    public void close() { //?timer_close77        System.out.println("  [Timer] " + operationName + " took " + elapsedMs + "ms"); //?print_elapsed78    }79}8081// Counter resource - tracks count //?counter_class82class Counter implements AutoCloseable { //?counter_def83    private int count = 0; //?count_field84    private boolean closed = false; //?closed_field8586    public void increment() { //?increment_method87        checkNotClosed(); //?check_increment88        count++; //?do_increment89    }9091    public int getCount() { //?get_count92        checkNotClosed(); //?check_get93        return count; //?return_count94    }9596    private void checkNotClosed() { //?check_not_closed97        if (closed) { //?if_closed98            throw new IllegalStateException("Counter is closed"); //?throw_closed99        }100    }101102    @Override103    public void close() { //?counter_close104        if (!closed) { //?if_not_closed105            System.out.println("  [Counter] Final count: " + count); //?print_final106            closed = true; //?set_closed107        }108    }109}110111// Resource that handles close errors gracefully //?safe_resource_class112class SafeResource implements AutoCloseable { //?safe_resource_def113114    public void process() { //?process_method115        System.out.println("  [SafeResource] Processing..."); //?print_processing116    }117118    @Override119    public void close() { //?safe_close120        System.out.println("  [SafeResource] Closing..."); //?print_closing121        try { //?try_cleanup122            // Simulate cleanup that might fail //?simulate_cleanup123            performCleanup(); //?do_cleanup124        } catch (Exception e) { //?catch_cleanup125            // Log but don't rethrow //?log_comment126            System.out.println("  [SafeResource] Cleanup warning: " + e.getMessage()); //?print_warning127        }128        System.out.println("  [SafeResource] Closed (even if cleanup had issues)"); //?print_closed129    }130131    private void performCleanup() { //?perform_cleanup132        // In real code, this might fail //?might_fail133        System.out.println("  [SafeResource] Cleanup succeeded"); //?cleanup_success134    }135}136137// Resource with idempotent close //?idempotent_class138class IdempotentResource implements AutoCloseable { //?idempotent_def139    private boolean closed = false; //?idempotent_closed140    private int closeCallCount = 0; //?close_call_count141142    public void use() { //?use_method143        if (closed) throw new IllegalStateException("Already closed"); //?check_use144        System.out.println("  [Idempotent] Using resource"); //?print_using145    }146147    @Override148    public void close() { //?idempotent_close149        closeCallCount++; //?increment_count150        System.out.println("  [Idempotent] close() called (call #" + closeCallCount + ")"); //?print_call151152        if (!closed) { //?first_close_check153            closed = true; //?do_close154            System.out.println("  [Idempotent] Actually closing resources"); //?actually_close155        } else {156            System.out.println("  [Idempotent] Already closed, doing nothing"); //?already_closed157        }158    }159}160161// Resource with cleanup callback //?callback_class162class CallbackResource implements AutoCloseable { //?callback_def163    private final Runnable cleanupAction; //?cleanup_action_field164165    public CallbackResource(Runnable cleanupAction) { //?callback_constructor166        this.cleanupAction = cleanupAction;167        System.out.println("  [Callback] Resource created"); //?print_created168    }169170    public void process() { //?callback_process171        System.out.println("  [Callback] Processing..."); //?print_callback_process172    }173174    @Override175    public void close() { //?callback_close176        System.out.println("  [Callback] Closing..."); //?print_callback_close177        cleanupAction.run(); //?run_cleanup178    }⋯

⋯3public class SuppressedExceptions {4    public static void main(String[] args) {5        System.out.println("=== Suppressed Exceptions ===\n");67        // When both try body and close() throw //?both_throw8        System.out.println("--- Exception in Try Body AND close() ---");⋯

⋯121public ThrowingResource(String namedefault) { //?throwing_constructor122    this.name→ default = namedefault;123    System.out.println("  [" + namedefault + "] Opened"); //?print_throwing_opened124}⋯

⋯10try { //?try_both11    try (ThrowingResource resource⟨ThrowingResource A⟩ = new ThrowingResource()) { //?try_throwing12        resource.doWork(); //?do_work_throws13        throw new RuntimeException("Error in try body"); //?throw_body⋯

⋯11            try (ThrowingResource resource = new ThrowingResource()) { //?try_throwing12                resource.doWork(); //?do_work_throws13                throw new RuntimeException("Error in try body"); //?throw_body14            }15        } catch (Exception e) { //?catch_both16            System.out.println("Primary exception: " + e.getMessage()); //?print_primary1718            Throwable[] suppressed = e.getSuppressed(); //?get_suppressed19            System.out.println("Suppressed exceptions: " + suppressed.length); //?print_suppressed_count2021            for (Throwable t : suppressed) { //?loop_suppressed22                System.out.println("  - " + t.getMessage()); //?print_suppressed23            }24        }2526        // Multiple resources, multiple close failures //?multiple_failures27        System.out.println("\n--- Multiple Resources Failing to Close ---");2829        try { //?try_multiple30            try ( //?try_multi_resources31                ThrowingResource r1 = new ThrowingResource("first"); //?first_throwing32                ThrowingResource r2 = new ThrowingResource("second"); //?second_throwing33                ThrowingResource r3 = new ThrowingResource("third") //?third_throwing34            ) {35                throw new RuntimeException("Main error"); //?main_error36            }37        } catch (Exception e) { //?catch_multiple38            System.out.println("Primary: " + e.getMessage()); //?print_multi_primary39            System.out.println("Suppressed:"); //?suppressed_header40            for (Throwable t : e.getSuppressed()) { //?loop_multi_suppressed41                System.out.println("  - " + t.getMessage()); //?print_multi_suppressed42            }43        }4445        // Only close() throws (no exception in try body) //?only_close_throws46        System.out.println("\n--- Only close() Throws ---");4748        try { //?try_only_close49            try (ThrowingResource resource = new ThrowingResource()) { //?try_throwing_only50                resource.doWork(); //?work_no_throw51                System.out.println("  Work completed successfully"); //?work_success52                // No exception here //?no_exception_comment53            }54        } catch (Exception e) { //?catch_only_close55            System.out.println("Exception from close(): " + e.getMessage()); //?print_close_exception56            System.out.println("Suppressed: " + e.getSuppressed().length); //?print_suppressed_only57        }5859        // Examining suppressed exceptions //?examine60        System.out.println("\n--- Examining Suppressed Exceptions ---");6162        try { //?try_examine63            try (ExamineResource resource = new ExamineResource()) { //?try_examine_resource64                throw new RuntimeException("Primary failure"); //?primary_failure65            }66        } catch (Exception e) { //?catch_examine67            printExceptionTree(e, 0); //?print_tree68        }6970        // Manually adding suppressed exceptions //?manual_suppress71        System.out.println("\n--- Manually Adding Suppressed ---");7273        Exception primary = new Exception("Primary error"); //?create_primary74        primary.addSuppressed(new Exception("Cleanup error 1")); //?add_suppressed175        primary.addSuppressed(new Exception("Cleanup error 2")); //?add_suppressed27677        System.out.println("Primary: " + primary.getMessage()); //?print_manual_primary78        for (Throwable t : primary.getSuppressed()) { //?loop_manual79            System.out.println("  Suppressed: " + t.getMessage()); //?print_manual_suppressed80        }8182        System.out.println("\n=== Key Points ===");83        System.out.println("""84            1. If try body throws, that's the PRIMARY exception85            2. If close() also throws, it's SUPPRESSED86            3. Access suppressed via getSuppressed()87            4. Multiple close() failures → multiple suppressed88            5. If only close() throws, that becomes the primary89            6. Suppressed exceptions preserve all error information90            """);91    }9293    static void printExceptionTree(Throwable t, int indent) { //?print_tree_method94        String prefix = "  ".repeat(indent); //?calc_prefix95        System.out.println(prefix + "Exception: " + t.getClass().getSimpleName()); //?print_type96        System.out.println(prefix + "  Message: " + t.getMessage()); //?print_message9798        Throwable[] suppressed = t.getSuppressed(); //?get_tree_suppressed99        if (suppressed.length > 0) { //?check_has_suppressed100            System.out.println(prefix + "  Suppressed:"); //?print_suppressed_header101            for (Throwable s : suppressed) { //?loop_tree102                printExceptionTree(s, indent + 2); //?recursive_call103            }104        }105106        if (t.getCause() != null) { //?check_cause107            System.out.println(prefix + "  Caused by:"); //?print_cause_header108            printExceptionTree(t.getCause(), indent + 2); //?recursive_cause109        }110    }111}112113// Resource that throws on close //?throwing_resource_class114class ThrowingResource implements AutoCloseable { //?throwing_def115    private final String name; //?throwing_name116117    public ThrowingResource() { //?throwing_constructor_default118        this("default");119    }120121    public ThrowingResource(String name) { //?throwing_constructor122        this.name = name;123        System.out.println("  [" + name + "] Opened"); //?print_throwing_opened124    }125126    public void doWork() { //?throwing_work127        System.out.println("  [" + namedefault + "] Working..."); //?print_throwing_work128    }⋯

⋯130@Override131public void close() { //?throwing_close132    System.out.println("  [" + namedefault + "] Closing (will throw)..."); //?print_throwing_close133    throw new RuntimeException("Error closing " + name); //?throw_close_error134}⋯

⋯14    }15} catch (Exception ejava.lang.RuntimeException: Error in try body) { //?catch_both16    System.out.println("Primary exception: " + e.getMessage()); //?print_primary1718    Throwable[] suppressed = e.getSuppressed(); //?get_suppressed19    System.out.println("Suppressed exceptions: " + suppressed.length1); //?print_suppressed_count⋯

⋯21for (Throwable tjava.lang.RuntimeException: Error closing default : suppressed) { //?loop_suppressed22    System.out.println("  - " + t.getMessage()); //?print_suppressed23}⋯

⋯26// Multiple resources, multiple close failures //?multiple_failures27System.out.println("\n--- Multiple Resources Failing to Close ---");⋯

⋯29try { //?try_multiple30    try ( //?try_multi_resources31        ThrowingResource r1⟨ThrowingResource B⟩ = new ThrowingResource("first"); //?first_throwing32        ThrowingResource r2⟨ThrowingResource C⟩ = new ThrowingResource("second"); //?second_throwing33        ThrowingResource r3⟨ThrowingResource D⟩ = new ThrowingResource("third") //?third_throwing34    ) {35        throw new RuntimeException("Main error"); //?main_error36    }⋯

⋯36    }37} catch (Exception ejava.lang.RuntimeException: Main error) { //?catch_multiple38    System.out.println("Primary: " + e.getMessage()); //?print_multi_primary39    System.out.println("Suppressed:"); //?suppressed_header40    for (Throwable t : e.getSuppressed()) { //?loop_multi_suppressed⋯

⋯39System.out.println("Suppressed:"); //?suppressed_header40for (Throwable tjava.lang.RuntimeException: Error closing third : e.getSuppressed()) { //?loop_multi_suppressed41    System.out.println("  - " + t.getMessage()); //?print_multi_suppressed42}⋯

⋯45// Only close() throws (no exception in try body) //?only_close_throws46System.out.println("\n--- Only close() Throws ---");⋯

⋯48try { //?try_only_close49    try (ThrowingResource resource⟨ThrowingResource E⟩ = new ThrowingResource()) { //?try_throwing_only50        resource.doWork(); //?work_no_throw51        System.out.println("  Work completed successfully"); //?work_success⋯

⋯49            try (ThrowingResource resource = new ThrowingResource()) { //?try_throwing_only50                resource.doWork(); //?work_no_throw51                System.out.println("  Work completed successfully"); //?work_success52                // No exception here //?no_exception_comment53            }54        } catch (Exception e) { //?catch_only_close55            System.out.println("Exception from close(): " + e.getMessage()); //?print_close_exception56            System.out.println("Suppressed: " + e.getSuppressed().length); //?print_suppressed_only57        }5859        // Examining suppressed exceptions //?examine60        System.out.println("\n--- Examining Suppressed Exceptions ---");6162        try { //?try_examine63            try (ExamineResource resource = new ExamineResource()) { //?try_examine_resource64                throw new RuntimeException("Primary failure"); //?primary_failure65            }66        } catch (Exception e) { //?catch_examine67            printExceptionTree(e, 0); //?print_tree68        }6970        // Manually adding suppressed exceptions //?manual_suppress71        System.out.println("\n--- Manually Adding Suppressed ---");7273        Exception primary = new Exception("Primary error"); //?create_primary74        primary.addSuppressed(new Exception("Cleanup error 1")); //?add_suppressed175        primary.addSuppressed(new Exception("Cleanup error 2")); //?add_suppressed27677        System.out.println("Primary: " + primary.getMessage()); //?print_manual_primary78        for (Throwable t : primary.getSuppressed()) { //?loop_manual79            System.out.println("  Suppressed: " + t.getMessage()); //?print_manual_suppressed80        }8182        System.out.println("\n=== Key Points ===");83        System.out.println("""84            1. If try body throws, that's the PRIMARY exception85            2. If close() also throws, it's SUPPRESSED86            3. Access suppressed via getSuppressed()87            4. Multiple close() failures → multiple suppressed88            5. If only close() throws, that becomes the primary89            6. Suppressed exceptions preserve all error information90            """);91    }9293    static void printExceptionTree(Throwable t, int indent) { //?print_tree_method94        String prefix = "  ".repeat(indent); //?calc_prefix95        System.out.println(prefix + "Exception: " + t.getClass().getSimpleName()); //?print_type96        System.out.println(prefix + "  Message: " + t.getMessage()); //?print_message9798        Throwable[] suppressed = t.getSuppressed(); //?get_tree_suppressed99        if (suppressed.length > 0) { //?check_has_suppressed100            System.out.println(prefix + "  Suppressed:"); //?print_suppressed_header101            for (Throwable s : suppressed) { //?loop_tree102                printExceptionTree(s, indent + 2); //?recursive_call103            }104        }105106        if (t.getCause() != null) { //?check_cause107            System.out.println(prefix + "  Caused by:"); //?print_cause_header108            printExceptionTree(t.getCause(), indent + 2); //?recursive_cause109        }110    }111}112113// Resource that throws on close //?throwing_resource_class114class ThrowingResource implements AutoCloseable { //?throwing_def115    private final String name; //?throwing_name116117    public ThrowingResource() { //?throwing_constructor_default118        this("default");119    }120121    public ThrowingResource(String name) { //?throwing_constructor122        this.name = name;123        System.out.println("  [" + name + "] Opened"); //?print_throwing_opened124    }125126    public void doWork() { //?throwing_work127        System.out.println("  [" + namedefault + "] Working..."); //?print_throwing_work128    }⋯

⋯53    }54} catch (Exception ejava.lang.RuntimeException: Error closing default) { //?catch_only_close55    System.out.println("Exception from close(): " + e.getMessage()); //?print_close_exception56    System.out.println("Suppressed: " + e.getSuppressed().length); //?print_suppressed_only57}⋯

⋯59// Examining suppressed exceptions //?examine60System.out.println("\n--- Examining Suppressed Exceptions ---");⋯

⋯140public ExamineResource() { //?examine_constructor141    System.out.println("  [ExamineResource] Opened"); //?print_examine_open142}⋯

⋯62try { //?try_examine63    try (ExamineResource resource⟨ExamineResource F⟩ = new ExamineResource()) { //?try_examine_resource64        throw new RuntimeException("Primary failure"); //?primary_failure65    }⋯

⋯144@Override145public void close() { //?examine_close146    System.out.println("  [ExamineResource] Closing..."); //?print_examine_close147    RuntimeException closeError→ java.lang.RuntimeException: Close failed = new RuntimeException("Close failed"); //?create_close_error148    closeError.initCause(new RuntimeException("Underlying cause")); //?set_cause149    throw closeErrorjava.lang.RuntimeException: Close failed; //?throw_with_cause150}⋯

⋯65    }66} catch (Exception ejava.lang.RuntimeException: Primary failure) { //?catch_examine67    printExceptionTree(ejava.lang.RuntimeException: Primary failure, 0); //?print_tree68}⋯

⋯93static void printExceptionTree(Throwable tjava.lang.RuntimeException: Primary failure, int indent0) { //?print_tree_method94    String prefix→ (empty) = "  ".repeat(indent0); //?calc_prefix95    System.out.println(prefix(empty) + "Exception: " + t.getClass().getSimpleName()); //?print_type96    System.out.println(prefix(empty) + "  Message: " + t.getMessage()); //?print_message9798    Throwable[] suppressed = t.getSuppressed(); //?get_tree_suppressed99    if (suppressed.length > 0) { //?check_has_suppressed⋯

⋯98Throwable[] suppressed = t.getSuppressed(); //?get_tree_suppressed99if (suppressed.length1 > 0) { //?check_has_suppressed100    System.out.println(prefix(empty) + "  Suppressed:"); //?print_suppressed_header101    for (Throwable s : suppressed) { //?loop_tree⋯

⋯100System.out.println(prefix + "  Suppressed:"); //?print_suppressed_header101for (Throwable sjava.lang.RuntimeException: Close failed : suppressed) { //?loop_tree102    printExceptionTree(sjava.lang.RuntimeException: Close failed, indent0 + 2); //?recursive_call103}⋯

⋯106if (t.getCause() != null) { //?check_cause107    System.out.println(prefix     + "  Caused by:"); //?print_cause_header108    printExceptionTree(t.getCause(), indent2 + 2); //?recursive_cause109}⋯

⋯77System.out.println("Primary: " + primary.getMessage()); //?print_manual_primary78for (Throwable tjava.lang.Exception: Cleanup error 1 : primary.getSuppressed()) { //?loop_manual79    System.out.println("  Suppressed: " + t.getMessage()); //?print_manual_suppressed80}⋯

⋯77System.out.println("Primary: " + primary.getMessage()); //?print_manual_primary78for (Throwable tjava.lang.Exception: Cleanup error 2 : primary.getSuppressed()) { //?loop_manual79    System.out.println("  Suppressed: " + t.getMessage()); //?print_manual_suppressed80}⋯

⋯82    System.out.println("\n=== Key Points ===");83    System.out.println("""84        1. If try body throws, that's the PRIMARY exception85        2. If close() also throws, it's SUPPRESSED86        3. Access suppressed via getSuppressed()87        4. Multiple close() failures → multiple suppressed88        5. If only close() throws, that becomes the primary89        6. Suppressed exceptions preserve all error information90        """);91}⋯

⋯3public class Java9Enhancement {4    public static void main(String[] args) {5        System.out.println("=== Java 9+ Try-with-Resources Enhancement ===\n");67        // Java 7/8 style - must declare in try() //?java7_style8        System.out.println("--- Java 7/8 Style ---");9        java7Style(); //?call_java7⋯

⋯138public MyResource(String namejava7) { //?resource_constructor139    this.name→ java7 = namejava7;140    System.out.println("  [" + namejava7 + "] Created"); //?print_created141}⋯

⋯39// Must declare in try parentheses //?must_declare40try (MyResource resource⟨MyResource A⟩ = new MyResource("java7")) { //?try_java741    resource.use(); //?use_java742}⋯

⋯40        try (MyResource resource = new MyResource("java7")) { //?try_java741            resource.use(); //?use_java742        }4344        // Can't do this in Java 7/8: //?cant_do45        // MyResource existing = new MyResource("x");46        // try (existing) { ... }  // Compile error in Java 7/847    }4849    static void java9Style() { //?java9_method50        // Create resource outside try //?create_outside51        MyResource resource = new MyResource("java9"); //?create_resource5253        // Use existing variable in try (Java 9+) //?use_existing54        // Just reference the variable!55        try (resource) { //?try_java956            resource.use(); //?use_java957        }58        // resource is now closed //?closed_comment59    }6061    static void multipleExistingVariables() { //?multiple_method62        // Create multiple resources //?create_multiple63        MyResource r1 = new MyResource("resource1"); //?create_r164        MyResource r2 = new MyResource("resource2"); //?create_r26566        // Use both in try //?use_both67        // Semicolon separated68        try (r1; r2) { //?try_multiple69            r1.use(); //?use_r170            r2.use(); //?use_r271        }72    }7374    static void mixedStyle() { //?mixed_method75        // Existing resource //?existing_for_mixed76        MyResource existing = new MyResource("existing"); //?create_existing7778        // Mix new declaration with existing variable //?mix_declaration79        try ( //?try_mixed80            existing; // Existing variable81            MyResource newOne = new MyResource("new") // New declaration82        ) {83            existing.use(); //?use_existing_mixed84            newOne.use(); //?use_new_mixed85        }86    }8788    static void whyEffectivelyFinal() { //?why_final_method89        MyResource resource = new MyResource("demo"); //?create_demo9091        // This would make it NOT effectively final: //?not_final_comment92        // resource = new MyResource("other");  // Reassignment9394        // Because 'resource' is never reassigned, it's effectively final //?effectively_final95        try (resource) { //?try_final96            resource.use(); //?use_final97        }9899        // This WON'T compile: //?wont_compile100        /*101        MyResource mutable = new MyResource("a");102        mutable = new MyResource("b");  // Reassignment makes it not effectively final103        try (mutable) {  // Compile error!104            mutable.use();105        }106        */107        System.out.println("  'resource' was effectively final, so it worked!"); //?final_worked108    }109110    // Useful with method parameters //?method_params111    static void processResource(MyResource resource) { //?process_method112        // Parameters are effectively final by default //?params_final113        try (resource) { //?try_param114            resource.use(); //?use_param115        }116    }117118    // Useful with factory methods //?factory_methods119    static void withFactory() { //?factory_demo120        // Factory creates resource //?factory_creates121        MyResource resource = createResource(); //?call_factory122123        // Use it in try //?use_factory_result124        try (resource) { //?try_factory125            resource.use(); //?use_factory_resource126        }127    }128129    static MyResource createResource() { //?create_resource_method130        return new MyResource("from factory"); //?return_factory131    }132}133134// Resource class //?resource_class135class MyResource implements AutoCloseable { //?resource_def136    private final String name; //?resource_name137138    public MyResource(String name) { //?resource_constructor139        this.name = name;140        System.out.println("  [" + name + "] Created"); //?print_created141    }142143    public void use() { //?use_method144        System.out.println("  [" + namejava7 + "] Being used"); //?print_used145    }⋯

⋯8        System.out.println("--- Java 7/8 Style ---");9        java7Style(); //?call_java71011        // Java 9+ style - can use existing effectively final variable //?java9_style12        System.out.println("\n--- Java 9+ Style ---");13        java9Style(); //?call_java91415        // Multiple existing variables //?multiple_existing16        System.out.println("\n--- Multiple Existing Variables (Java 9+) ---");17        multipleExistingVariables(); //?call_multiple1819        // Mixed: some new, some existing //?mixed_style20        System.out.println("\n--- Mixed Style (Java 9+) ---");21        mixedStyle(); //?call_mixed2223        // Why effectively final matters //?why_final24        System.out.println("\n--- Why 'Effectively Final' Matters ---");25        whyEffectivelyFinal(); //?call_why_final2627        System.out.println("\n=== Key Points ===");28        System.out.println("""29            Java 9+ Enhancement:30            1. Can use existing effectively final variables31            2. Variable must be final or effectively final32            3. Makes code cleaner when resource already exists33            4. Can mix new declarations and existing variables34            5. Useful with method parameters and factory methods35            """);36    }3738    static void java7Style() { //?java7_method39        // Must declare in try parentheses //?must_declare40        try (MyResource resource = new MyResource("java7")) { //?try_java741            resource.use(); //?use_java742        }4344        // Can't do this in Java 7/8: //?cant_do45        // MyResource existing = new MyResource("x");46        // try (existing) { ... }  // Compile error in Java 7/847    }4849    static void java9Style() { //?java9_method50        // Create resource outside try //?create_outside51        MyResource resource = new MyResource("java9"); //?create_resource5253        // Use existing variable in try (Java 9+) //?use_existing54        // Just reference the variable!55        try (resource) { //?try_java956            resource.use(); //?use_java957        }58        // resource is now closed //?closed_comment59    }6061    static void multipleExistingVariables() { //?multiple_method62        // Create multiple resources //?create_multiple63        MyResource r1 = new MyResource("resource1"); //?create_r164        MyResource r2 = new MyResource("resource2"); //?create_r26566        // Use both in try //?use_both67        // Semicolon separated68        try (r1; r2) { //?try_multiple69            r1.use(); //?use_r170            r2.use(); //?use_r271        }72    }7374    static void mixedStyle() { //?mixed_method75        // Existing resource //?existing_for_mixed76        MyResource existing = new MyResource("existing"); //?create_existing7778        // Mix new declaration with existing variable //?mix_declaration79        try ( //?try_mixed80            existing; // Existing variable81            MyResource newOne = new MyResource("new") // New declaration82        ) {83            existing.use(); //?use_existing_mixed84            newOne.use(); //?use_new_mixed85        }86    }8788    static void whyEffectivelyFinal() { //?why_final_method89        MyResource resource = new MyResource("demo"); //?create_demo9091        // This would make it NOT effectively final: //?not_final_comment92        // resource = new MyResource("other");  // Reassignment9394        // Because 'resource' is never reassigned, it's effectively final //?effectively_final95        try (resource) { //?try_final96            resource.use(); //?use_final97        }9899        // This WON'T compile: //?wont_compile100        /*101        MyResource mutable = new MyResource("a");102        mutable = new MyResource("b");  // Reassignment makes it not effectively final103        try (mutable) {  // Compile error!104            mutable.use();105        }106        */107        System.out.println("  'resource' was effectively final, so it worked!"); //?final_worked108    }109110    // Useful with method parameters //?method_params111    static void processResource(MyResource resource) { //?process_method112        // Parameters are effectively final by default //?params_final113        try (resource) { //?try_param114            resource.use(); //?use_param115        }116    }117118    // Useful with factory methods //?factory_methods119    static void withFactory() { //?factory_demo120        // Factory creates resource //?factory_creates121        MyResource resource = createResource(); //?call_factory122123        // Use it in try //?use_factory_result124        try (resource) { //?try_factory125            resource.use(); //?use_factory_resource126        }127    }128129    static MyResource createResource() { //?create_resource_method130        return new MyResource("from factory"); //?return_factory131    }132}133134// Resource class //?resource_class135class MyResource implements AutoCloseable { //?resource_def136    private final String name; //?resource_name137138    public MyResource(String name) { //?resource_constructor139        this.name = name;140        System.out.println("  [" + name + "] Created"); //?print_created141    }142143    public void use() { //?use_method144        System.out.println("  [" + name + "] Being used"); //?print_used145    }146147    @Override148    public void close() { //?close_method149        System.out.println("  [" + namejava7 + "] Closed"); //?print_closed150    }⋯