Android Customized Toolbar causes java.lang.NoClassDefFoundError -

i'm trying implement customized toolbar face error

java.lang.noclassdeffounderror: class not found using boot class loader; no stack available

i have support library v4 & appcompat v7. tried every thing nothing works.

here code:

mainactivity.java

package com.example.customized_toolbar;    import java.util.arraylist; import java.util.zip.inflater;  import android.annotation.targetapi; import android.app.activity; import android.app.fragment; import android.app.fragmentmanager; import android.content.res.configuration; import android.content.res.typedarray; import android.os.build; import android.os.bundle; import android.support.v4.app.actionbardrawertoggle; import android.support.v4.widget.drawerlayout; import android.support.v7.app.appcompatactivity; import android.support.v7.widget.toolbar; import android.util.log; import android.view.*; import android.widget.adapterview; import android.widget.listview; import android.support.v7.app.actionbaractivity; import android.os.bundle; import android.view.menu; import android.view.menuitem; import android.support.v7.widget.toolbar; import android.widget.toast;   public class mainactivity extends appcompatactivity { /**  * called when activity first created.  */  toolbar mtoolbar; @override public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);        mtoolbar= (toolbar) findviewbyid(r.id.toolbar);     setsupportactionbar(mtoolbar);  }  private void setsupportactionbar(toolbar mtoolbar) { } 

}

activity_main.xml  <?xml version="1.0" encoding="utf-8"?> <include     xmlns:android="http://schemas.android.com/apk/res/android"      android:id="@+id/toolbar_actionbar"     layout="@layout/toolbar_default"     android:layout_width="match_parent"     android:layout_height="wrap_content"/> 

toolbar_default.xml

<?xml version="1.0" encoding="utf-8"?> <android.support.v7.widget.toolbar     xmlns:android="http://schemas.android.com/apk/res/android"      android:id="@+id/toolbar"     android:layout_width="match_parent"     android:layout_height="wrap_content">  </android.support.v7.widget.toolbar> 

the menu file main.xml:

<menu xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:app="http://schemas.android.com/apk/res-auto"   xmlns:tools="http://schemas.android.com/tools"   tools:context=".mainactivity"> <item android:id="@+id/action_reply"        android:title="reply"  />  <item android:id="@+id/action_undo"       android:title="undo"         />   </menu> 

styles.xml

<?xml version="1.0" encoding="utf-8"?> <resources> <style name="theme.appcompat.light"></style> <style name="theme"></style> <style name="theme.appcompat"></style> <style name="theme.appcompat.noactionbar"></style>  <style name="apptheme" parent="theme.appcompat.noactionbar"></style>  <style name="mytheme" parent="theme.appcompat.noactionbar">      <item name="android:windowactionbar">false</item>    </style>  </resources><br/>  

androidmanifest.xml

 <?xml version="1.0" encoding="utf-8"?>  <manifest xmlns:android="http://schemas.android.com/apk/res/android"       package="com.example.customized_toolbar"       android:versioncode="1"        android:versionname="1.0"> <uses-sdk android:minsdkversion="15"         android:targetsdkversion="21"/> <application android:label="@string/app_name"              android:theme="@style/mytheme"              android:icon="@drawable/ic_launcher">     <activity android:name="mainactivity"               android:label="@string/app_name"             android:theme="@style/mytheme">         <intent-filter>             <action android:name="android.intent.action.main"/>             <category android:name="android.intent.category.launcher"/>         </intent-filter>     </activity> </application> </manifest> 

change

 mtoolbar= (toolbar) findviewbyid(r.id.toolbar_actionbar); 

to

 mtoolbar= (toolbar) findviewbyid(r.id.toolbar); 

make sure mainactivity extends appcompatactivity instead of actionbaractivity

change

setsupportactionbar(mtoolbar); 

to

setsupportactionbar(mtoolbar); 

edit:

public class mainactivity extends appcompatactivity {      toolbar mtoolbar;     @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         mtoolbar= (toolbar) findviewbyid(r.id.toolbar);         setsupportactionbar(mtoolbar);      }       @override      public boolean oncreateoptionsmenu(menu menu)      {         menuinflater inflater = getmenuinflater();         inflater.inflate(r.menu.main, menu);         menu.getitem(0);         menu.getitem(1);         return super.oncreateoptionsmenu(menu);        }     }