SecurityManager sm = new SecurityManager();

sm.checkMemberAccess(Test.class, Member.PUBLIC);

package com.jd.basic.pk.manager;

import java.lang.reflect.Field;

import java.security.Permission;

public class UseReflection {

    static {

        try {

            System.setSecurityManager(new MySecurityManager());

        } catch (SecurityException se) {

            System.out.println("SecurityManager already set!");

        }

    }

    public static void main(String args[]) {

        Object prey = new Prey();

        try {

            Field pf = prey.getClass().getDeclaredField("privateString");

            pf.setAccessible(true);

            pf.set(prey, "Aminur test");

            System.out.println(pf.get(prey));

        } catch (Exception e) {

            System.err.println("Caught exception " + e.toString());

        }

    }

}

class Prey {

    @SuppressWarnings("unused")

    private String privateString = "privateValue";

}

class MySecurityManager extends SecurityManager {

    public void checkPermission(Permission perm) {

        if (perm.getName().equals("suppressAccessChecks")) {

            throw new SecurityException("Can not change the permission dude.!");

        }

    }

}