Cannot resolve symbol 'menu'
<p><a href="https://i.stack.imgur.com/IHpRQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IHpRQ.png" alt="MainActivity.java"></a></p>

<blockquote>
  <p>This activity_main.java</p>
</blockquote>

<h1>Main javaActity file</h1>

<p><em>imported packages and libraries</em></p>

<pre><code>//Package for project 
package com.example.legend.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

//Main activity main class extending Activity class

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    //Menu class

    @Override
    public boolean onCreateOptionMenu(Menu menu){
        getMenuInflater().inflate(R.menu.menu_main, menu);//Can't resolve  menu symbol
        return true;
    }
}
</code></pre>

<blockquote>
  <p>Manifest.xml file</p>
</blockquote>

<h1>AndroidManifest.xml File</h1>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.legend.myapplication"&gt;

&lt;application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"&gt;
    &lt;activity android:name=".MainActivity"&gt;
        &lt;intent-filter&gt;
            &lt;action android:name="android.intent.action.MAIN" /&gt;

            &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
        &lt;/intent-filter&gt;
    &lt;/activity&gt;
&lt;/application&gt;

&lt;/manifest&gt;
</code></pre>

<blockquote>
  <p>String.xml file</p>
  
  <h2>String Content file for app</h2>
</blockquote>

<pre><code>&lt;resources&gt;
    &lt;string name="app_name"&gt;XXXXXXXXXX&lt;/string&gt;
&lt;/resources&gt;
</code></pre>

<blockquote>
  <p>activity_main.xml</p>
  
  <h1>Activity_Main.xml</h1>
</blockquote>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:background="#da006699"
tools:context="com.example.legend.myapplication.MainActivity"&gt;

    &lt;TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="XXXXXXXXX"
        android:textColor="#ffffff"
        android:id="@+id/textView"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" /&gt;
&lt;/RelativeLayout&gt;
</code></pre>