Implementation of an OkHttp singleton for Android
You don't need to create new instance of OkHttpClient. Remove it.
You can use Initialization-on-demand holder pattern to create singleton in Java. No need to use synchronized block
Change coding style in your code. Remove m before instance variable. See naming convention.


Here is the code: 

public class OkSingleton extends OkHttpClient {
    private static class LazyHolder {
        private static final OkSingleton instance = new OkSingleton();
    }

    public static OkSingleton getInstance() {
        return LazyHolder.instance;
    }
}