Why isn't it necessary to assign a method's return value to a variable? [duplicate]

Answer 1

You can annotate a method with @CheckReturnValue if its return value should always be used. Static code analysis like FindBugs consider this annotation and raise warning when you violate it.

At least this is very reasonable when the method returns some kind of object that needs final processing at the end where the caller is responsible for. This is true for resources that must be closed at the end. Locks that must be released at the end ...