Actually, this is similar to what you can do in Java by using lambdas (Retrolambda for pre-Java 8, e.g. Android pre-SDK 24). Excerpt from a blog post [1] about

Actually, this is similar to what you can do in Java by using lambdas (Retrolambda for pre-Java 8, e.g. Android pre-SDK 24). Excerpt from a blog post [1] about it: mButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // do something here } }); can be replaced with mButton.setOnClickListener((View v) -> { // do something here }); which is nice for all callbacks, but especially together with ReactiveX where they are abundant. [1] http://zserge.com/blog/android-lambda.html http://zserge.com/blog/android-lambda.html