Getting Error NoClassDefFoundError

Question

I Am Getting NoClassDefFoundError Error Some Time I Couldn't able to find the issue

This is My Google Console Crash Report

java.lang.NoClassDefFoundError: 
at com.myapp.app.rise.networkoperations.NetworkService.onHandleIntent
at android.app.IntentService$ServiceHandler.handleMessage 
(IntentService.java:65)
at android.os.Handler.dispatchMessage (Handler.java:111)
at android.os.Looper.loop (Looper.java:210)
at android.os.HandlerThread.run (HandlerThread.java:61)

MY OnHandleIntent Method

protected void onHandleIntent(Intent intent) {
//Getting Exception Here NoClassDefFoundError
try {
if (Constants.isManualSyncInitiated) {
isManualSync = true;
Constants.isManualSyncInitiated = false;
}
}catch (ExceptionInInitializerError e){
e.printStackTrace();
}catch (Exception e){
e.printStackTrace();
}
if (WebServiceSingleTon.getInstance().isNetworkAvailable
(getApplicationContext())) {
ConstantsNonStatic constantsNonStatic = new ConstantsNonStatic();
dowanloadURL = constantsNonStatic.SYNC_DOWNLOAD_URL;
List<SyncMaster> syncQueue;
DBUtility db = new DBUtility(getApplicationContext());
syncQueue = db.getSyncDataToProcess();
InAppPurchaseUtility.getInAppProductPrivileges(getApplicationContext());
if (syncQueue.size() > 0) {
this.uploadContactsToCloud(syncQueue);
}
this.downloadContactsFromCloud();
}
}