set device screen lock unlock using reflection

I am using reflection to unlock my device screen setting keyguard as disabled.my android version is 4.4.2.while invoking i get exception as java.lang.reflect.InvocationTargetException and cause as java.lang.SecurityException: LockSettingsWrite: Neither user 10096 nor current process has android.permission.ACCESS_KEYGUARD_SECURE_STORAGE.

i am sharing my code please tell me how to rectify this exception

try{
   Class lockPatternUtilsCls = Class.forName("com.android.internal.widget.LockPatternUtils");
   Constructor lockPatternUtilsConstructor = lockPatternUtilsCls.getConstructor(new Class[]{Context.class});
   Object lockPatternUtils = lockPatternUtilsConstructor.newInstance(ChangeDeviceLockMode.this);

   Method clearLockMethod = lockPatternUtils.getClass().getMethod("clearLock", boolean.class);
   clearLockMethod.setAccessible(true);
   Method setLockScreenDisabledMethod = lockPatternUtils.getClass().getMethod("setLockScreenDisabled", boolean.class);
   setLockScreenDisabledMethod.setAccessible(true);
   clearLockMethod.invoke(lockPatternUtils, false);
   setLockScreenDisabledMethod.invoke(lockPatternUtils, true);     
   Toast.makeText(ChangeDeviceLockMode.this,"none", Toast.LENGTH_LONG).show();  
}catch(Exception e){
   System.err.println("An InvocationTargetException was caught!");
   Throwable cause = e.getCause();

   Toast.makeText(ChangeDeviceLockMode.this,"none"+e, Toast.LENGTH_LONG).show();  
}
Toast.makeText(ChangeDeviceLockMode.this,"Yupiee!!! Password changed successfully to swipe", Toast.LENGTH_LONG).show();  
}