One of the most common uses of anonymous classes are adapters for UI
events in Swing / AWT.  There the anonymous class implements an event
listener interface and reacts on evens in some way.

Kind regards

   robert

 
 For example, in BoxingShortable, the method "getShortable()"
 always returns the same instance x, which then, in turn,
 offers me an operation "get(short s)" to get a Short instance
 from a short value.

 This seems to be a Singleton object instead of a class with
 static methods.

 This seems to be done, because in Java, only instance-methods
 can implement interfaces, but not static methods.

 Otherwise, a static "get(short s)" method would have done.  Or
 are the even more reasons for this kind of implementation?

 It looks as if the whole source file is quite a large overhead
 and indirection for an operation that comes done to a method
 like "Short get(final short s){return s;}", which looks as if
 it would do nothing at all, but is using an autoboxing-
 conversion for its actual duty.

 In the end, there are about 86 lines to wrap this, plus at
 least one additional interface to describe it and test methods
 to test it and coverage tools to measure the coverage, and
 documentation and annotations for it all. All this overhead
 for effectively a single boxing conversion.

 I am not bringing up these questions to dispraise
 ContractualJ, I think I can learn by reading its source code.

 Regarding the rules on

http://contractualj.com/,

 I understand many of them and even use some of the myself, but
 what about:

     "All operations are defined on an interface, including
     private operations. Private methods are not permitted."

 So private operations are allowed, but private methods are
 not: I know the meaning of "private method" from the JLS, but
 what is a "private operation"?

 Also: Could it help to split the rules in two parts?
 Those which are DBC-related and those which are not?
 Avoiding "break;" might be good style, but has it
 directly to do with DBC?

 A rationale document for all these rules would be interesting
 to read.