How to Play with access modifiers at runtime

There are situations where you want to access private member variables . An example of this is trying to access the socket fd (descriptor) from the Socket implementation in Java for doing some jni operations on it. The file descriptor is stored as a private member variable in the Socket class, and can be accessed using this example. 

package org.best.example;




import java.lang.reflect.Field;

/**
* Class with the private variable
*/
class Hmmm
{
    //private variable only accessible from this class
    private int iWannaGoPublic=20; 
}


/**
* Class with code to access the private variable in Hmmm
*/
public class ChangeAccessExample
{
    public static void main(String[] args) throws Exception
    {
        Hmmm hmmmInstance=new Hmmm();
        Class hmmClass = hmmmInstance.getClass();
        Field f = hmmClass.getDeclaredField("iWannaGoPublic");
        f.setAccessible(true); //Make the variable accessible
        
        Object implVal = f.get(hmmmInstance);
        int fd=((Integer) implVal).intValue();
        
        System.out.println("Value of the private var is" + fd);
        //Let me restore the access before someone finds out :-)
        f.setAccessible(false);
    }
}