Method Lookup

Reflection can locate a method by name and parameter types, then invoke it.

MethodLookup.java

import java.lang.reflect.Method;

public class MethodLookup {
    static class Calculator {
        static int twice(int value) {
            return value * 2;
        }
    }

    public static void main(String[] args) throws Exception {
        int value = ;
        Method method = Calculator.class.getDeclaredMethod("twice", int.class);
        int result = (int) method.invoke(null, value);

        System.out.println("result=" + result);
    }
}

import java.lang.reflect.Method;

public class MethodLookup {
    static class Calculator {
        static int twice(int value) {
            return value * 2;
        }
    }

    public static void main(String[] args) throws Exception {
        int value = ;
        Method method = Calculator.class.getDeclaredMethod("twice", int.class);
        int result = (int) method.invoke(null, value);

        System.out.println("result=" + result);
    }
}

import java.lang.reflect.Method;

public class MethodLookup {
    static class Calculator {
        static int twice(int value) {
            return value * 2;
        }
    }

    public static void main(String[] args) throws Exception {
        int value = ;
        Method method = Calculator.class.getDeclaredMethod("twice", int.class);
        int result = (int) method.invoke(null, value);

        System.out.println("result=" + result);
    }
}

method metadata A Method object describes one method, including its name and parameter list.

invoke Calling invoke runs the reflected method with the supplied receiver and arguments.