//FinalTest
class FinalTest {
    public static void main(String[] args) {
        try {
            Field field = TestHelper.class.getDeclaredField("ENTITY");
            field.setAccessible(true);
            Entity entity = new Entity("reflection name");
            field.set(null, entity);
        } catch (Exception e) {
            e.printStackTrace();
        }

        System.out.println(TestHelper.getENTITY().name);
    }



    static class Entity {

        public String name;

        public Entity(String name) {
            this.name = name;
        }
    }
}


//..TestHelper
class TestHelper {
    private static final FinalTest.Entity ENTITY;

    static {
        ENTITY = new FinalTest.Entity("init name");
    }

    public static FinalTest.Entity getENTITY() {
        return ENTITY;
    }
}

tried to modify the ENTITY field in TestHelper by reflection, but failed. It hasn"t been modified. And threw an exception.

 Can not set static final com.company.finaltest.Entity field

java.lang.IllegalAccessException: Can not set static final com.company.finaltest.Entity field com.company.finaltest.TestHelper.ENTITY to com.company.finaltest.Entity
    at sun.reflect.UnsafeFieldAccessorImpl.throwFinalFieldIllegalAccessException(UnsafeFieldAccessorImpl.java:76)
    at sun.reflect.UnsafeFieldAccessorImpl.throwFinalFieldIllegalAccessException(UnsafeFieldAccessorImpl.java:80)
    at sun.reflect.UnsafeQualifiedStaticObjectFieldAccessorImpl.set(UnsafeQualifiedStaticObjectFieldAccessorImpl.java:77)
    at java.lang.reflect.Field.set(Field.java:764)
    at com.company.finaltest.FinalTest.main(FinalTest.java:13)

so I wonder why the initial code can change the value of final?

-
is it because my code has been optimized by the compiler?