XML : android.support.v7.widget.toolbar is not found in java file using android studio?

I have created a toolbar xml file and want to add in MainActivity.

i have include toolbar.xml file in MainActivity layout file

Toolbar.xml code:

  <?xml version="1.0" encoding="utf-8"?>  <android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"      android:layout_width="match_parent"      android:layout_height="?attr/actionBarSize"      android:background="@color/dark_blue">    </android.support.v7.widget.Toolbar>    

Main Activity Xml Layout :

  <?xml version="1.0" encoding="utf-8"?>  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"      xmlns:tools="http://schemas.android.com/tools"      android:layout_width="match_parent"      android:layout_height="match_parent"      tools:context="hogwart.harrypotter.bucketdrop.ActivityMain">        <include          android:id="@+id/toolbar"          layout="@layout/toolbar"/>      <include layout="@layout/empty_drops"/>  </RelativeLayout>    

Then i want to add toolbar to main activity via java code but here it shows one toolbar :

  import android.widget.Toolbar;    

But support toolbar is not found :

  import android.support.v7.widget.Toolbar;    

Main Activity Code:

  import android.os.Bundle;  import android.support.v7.app.AppCompatActivity;  import android.widget.Toolbar;    public class ActivityMain extends AppCompatActivity {        Toolbar      @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);      }  }    

Gradle file code:

  apply plugin: 'com.android.application'    android {      compileSdkVersion 23      buildToolsVersion "23.0.2"        defaultConfig {          applicationId "hogwart.harrypotter.bucketdrop"          minSdkVersion 15          targetSdkVersion 23          versionCode 1          versionName "1.0"      }      buildTypes {          release {              minifyEnabled false              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'          }      }  }    dependencies {      compile fileTree(dir: 'libs', include: ['*.jar'])      testCompile 'junit:junit:4.12'      compile 'com.android.support:appcompat-v7:23.1.0'  }