Modifying final fields in Java

Question

Let\'s start with a simple test case:

import java.lang.reflect.Field;

public class Test {
  private final int primitiveInt = 42;
  private final Integer wra         


        

Answer 1

In my opinion this is even worse: A colleague pointed to the following funny thing:

@Test public void  testInteger() throws SecurityException,  NoSuchFieldException, IllegalArgumentException, IllegalAccessException  {      
    Field value = Integer.class.getDeclaredField("value");      
    value.setAccessible(true);       
    Integer manipulatedInt = Integer.valueOf(7);      
    value.setInt(manipulatedInt, 666);       
    Integer testInt = Integer.valueOf(7);      
    System.out.println(testInt.toString());
}

By doing this, you can change the behaviour of the whole JVM you are running in. (of course you can change only the values for the values between -127 and 127)