Field Access

Reflection can look up a field and read its value from an object.

FieldAccess.java

import java.lang.reflect.Field;

public class FieldAccess {
    static class Box {
        public int value;

        Box(int value) {
            this.value = value;
        }
    }

    public static void main(String[] args) throws Exception {
        int start = ;
        Box box = new Box(start);
        Field field = Box.class.getDeclaredField("value");
        int loaded = (int) field.get(box);

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

import java.lang.reflect.Field;

public class FieldAccess {
    static class Box {
        public int value;

        Box(int value) {
            this.value = value;
        }
    }

    public static void main(String[] args) throws Exception {
        int start = ;
        Box box = new Box(start);
        Field field = Box.class.getDeclaredField("value");
        int loaded = (int) field.get(box);

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

import java.lang.reflect.Field;

public class FieldAccess {
    static class Box {
        public int value;

        Box(int value) {
            this.value = value;
        }
    }

    public static void main(String[] args) throws Exception {
        int start = ;
        Box box = new Box(start);
        Field field = Box.class.getDeclaredField("value");
        int loaded = (int) field.get(box);

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

field metadata A Field object describes one field declared on a class.

reflected read Calling get on a Field reads that field from a specific object.