Tuesday, 13 October 2015

Accessing Private Methods using Java Reflection

Accessing Private Methods

Call Class.getDeclaredMethod(String name, Class[] paramTypes) or Class.getDeclaredMethods() method to obtain the private/public methods.

The methods Class.getMethod(String name, Class[] parameterTypes) and Class.getMethods() methods only return public methods.

package reflection;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
class PrivateObject  {
      private String string;
      public PrivateObject (String string) {

      private String getPrivateMethod() {
            return string;

public class TestReflectionMethod {
      public static void main(String[] args) {
          PrivateObject pvtObj = new PrivateObject("Private method");
          try {
              Method privateMethod =

              /** SecurityException - if the request is denied. */

              String returnValue =
                           (String) privateMethod.invoke(pvtObj, null);

              System.out.println("using reflection="+returnValue+" accessed!!");

         } catch (IllegalAccessException e) {
         } catch (InvocationTargetException e) {
         } catch (NoSuchMethodException e) {

Output: using reflection = Private method accessed!!

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