How to solve "java.lang.NoClassDefFoundError" in Unity Android Plugin ?

Hello Guys, I was making Android Unity Plugin(Android Studio Library Project) to show a simple local Notification
on Button Click. But i am getting the above exception.

Thankyou

LOGCAT FROM ANDROID MONITOR

    09-17 10:06:33.762 3253-3274/? I/Unity: UnityEngine.AndroidJavaException: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/support/v4/app/NotificationCompat$Builder;
                                            java.lang.NoClassDefFoundError: Failed resolution of: Landroid/support/v4/app/NotificationCompat$Builder;
                                                at first.unityplugin.com.unitylibrary_1.Notification.ShowNotification(Notification.java:16)
                                                at com.unity3d.player.UnityPlayer.nativeRender(Native Method)
                                                at com.unity3d.player.UnityPlayer.a(Unknown Source)
                                                at com.unity3d.player.UnityPlayer$c$1.handleMessage(Unknown Source)
                                                at android.os.Handler.dispatchMessage(Handler.java:98)
                                                at android.os.Looper.loop(Looper.java:135)
                                                at com.unity3d.player.UnityPlayer$c.run(Unknown Source)
                                             Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v4.app.NotificationCompat$Builder" on path: DexPathList[[zip file "/data/app/com.Origins.Plugin-1/base.apk"],nativeLibraryDirectories=[/data/app/com.Origins.Plugin-1/lib/arm, /vendor/lib, /system/lib]]
                                            	at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassL).

JAVA CODE FOR SHOWING NOTIFICATION

package first.unityplugin.com.unitylibrary_1;

import android.content.Context;


public class Notification {

    public static String ShowNotification(Context context)
    {
      try {
          android.support.v4.app.NotificationCompat.Builder builder = new android.support.v4.app.NotificationCompat.Builder(context)
                  .setSmallIcon(android.R.drawable.arrow_up_float)
                  .setContentText("Conntext Text")
                  .setContentTitle("Content Title");
         
          android.app.NotificationManager notificationManager = (android.app.NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
          notificationManager.notify(001, builder.build());
          return "Success";
      }
      catch(Exception e)
        {
return String.valueOf(e);
        }


    }

}

C# Code For Calling Method to Show Notification

public Text text;

public void ShowNotification()
	{
		#if UNITY_ANDROID
		try{
		string status ="Class Not Found" ;

		AndroidJavaClass NotificationClass = new AndroidJavaClass("first.unityplugin.com.unitylibrary_1.Notification");

			if(NotificationClass != null)
			{
				status = NotificationClass.CallStatic<string>("ShowNotification",context);
				text.text = status;
			}
			else{
				text.text = status;
			}
		}
		catch (Exception e)
		{
			string a = e.ToString();
			text.text = a;
			Debug.Log(a);
		}


		#endif
		
	}

Hi,
I had same problem. Have you fixed this problem?
Thanks for help