I want to make method that will check if the class instance is null or not.
Simply I know that i can use == null, but I want to know that is there any other
The easiest way to check is entity == null. There is no shorter way to do that.
Note that there is a method for this in the standard lib:
Objects.isNull(Object obj)
And another one which is the opposite of the above one:
Objects.nonNull(Object obj)
And there is yet another one which can be used to force a value to be not null, it throws a NullPointerException otherwise:
T Objects.requireNonNull(T obj);
Note: The Objects class was added in Java 7, but the isNull() and nonNull() methods were added only in Java 8.