title: How to define the application class and the Static variable in kotlin
body: <p>How to write the Equivalent code in kotlin, I need to use the static variable defined</p>
  
  <pre><code>public class ThisForThatApplication extends Application {
  
      static ThisForThatApplication appInstance;
  
      public static ThisForThatApplication getAppInstance() {
          if (appInstance == null) {
              appInstance = new ThisForThatApplication();
          }
          return appInstance;
      }
  }
  </code></pre>