A custom application class that provides global application context.

MyApp.java

//
// Copyright © 2017 Kalpesh Talkar. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// For support: https://gist.github.com/KalpeshTalkar/c4c7ccf8003c6214c11226b86c565bb7
//

import android.app.Application;
import android.content.Context;

/**
 * Created by kalpesh on 17/08/17.
 */

public class MyApp extends Application {

    /// application context variable
    private static Context context;

    @Override
    public void onCreate() {
        super.onCreate();
        // Set the application context
        context = getApplicationContext();
    }

    /// Get application context
    public static Context sharedContext() {
        return context;
    }
    
}

Register Application class in Manifest:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.you.yourapp">

    <application
        android:name=".MyApp"

Usage:
Context applicationContext = MyApp.sharedContext()