How is Java doc invariant for a class?

Question

I want to know exactly where the comment should go, and which keyword should I use, since I really can’t find an example on the Internet, should I, for example, do this?

/**
 * @invariant invariant example
 */
 public class Example {
 } 

Answer 1

There are several options

@ Contract annotations

Some examples

• @Contract ("_, null → null") - the method returns null if its second argument is zero.

• @Contract ("_, null → null; _ ,! null →! Null") - the method returns null if its second argument is null, and not null otherwise.

• @Contract ( "true → fail" ) - assertFalse() , true .

. https://www.jetbrains.com/help/idea/2016.2/contract-annotations.html.

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, https://docs.oracle.com/javase/7/docs/api/java/util/Map.html#put(K,%20V)

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