Question

In java or Android there are @Override annotations. What does it mean? I found that it is used when method is from subclass or inherited interface’s method, I want to know further and other is @SuppressWarnings its also Anonation, if yes how many annonation used by java and for which purpose.

Answer 1

This question is also answered here, and quite succinctly:
Android @Override usage

It’s an annotation that you can use to tell the compiler and your IDE that you intend the method that has that annotation to be an override of a super class method. They have warning/errors in case you make mistakes, for example if you intend to override a method but misspell it, if the annotation is there the IDE or the compiler will tell you that it is not in fact overriding the super class method and thus you can determine why and correct the misspelling.

This is all the more important for Android applications and activities for example, where all of the calls will be based on the activity lifecycle – and if you do not properly override the lifecycle methods they will never get called by the framework. Everything will compile fine, but your app will not work the way you intend it to. If you add the annotation, you’ll get an error.

In other words, if you add @Override this helps you make sure you are really overriding an existing method! Pretty darn useful.