GoF Design Patterns with examples using Java and UML

written by:
Benneth Christiansson (Ed.)
Mattias Forss,
Ivar Hagen,
Kent Hansson,
Johan Jonasson,
Mattias Jonasson,
Fredrik Lott,
Sara Olsson, and
Thomas Rosevall

Gof Design patterns

A very nice recap of the design patterns.

Notational Conventions

Notational Conventions explained for many specifications:-
http://tools.ietf.org/html/rfc2119

Find Bugs

Find Bugs is an eclipse plugin which shows the common errors in Java. I use the eclipse plugin, and as a Best Practice for java developers this should be used while development. :)

e.g.
For a piece of code the following error was received

When piece of code in given below:-

1. Long id = request.getId();
2.       
3. if(request == null || id == null) {
4.     throw new RuntimeException("id cannot be null");
5. }

Find the error if you can... :)

The check for request == null is fruitless, since if request is null the line 1 will fail. Below is provided the corrected code and thus removes the bug.

1. if(request == null || request.getId() == null) {
2.  throw new RuntimeException("id cannot be null");
3. }

Long id = request.getId();

A note of caution, the code inspection tools need to be used intelligently, it may sometimes flag code as bug that may have been done for some valid reason. Ignore them in this case.

Minimize memory footprint

An application to minimize memory footprint.

Minimem

The application can optimize the memory used. Some applications when run over a long time start hogging a lot of memory, this tools optimizes the memory usage and free it.

Mozilla is a good example of such a process (at least I was facing the issue) but is irreplaceable. :)

Pitfalls of SOA adoption

An old link about pitfalls of SOA adoption.

Pitfalls of SOA adoption - Thomas Erl

Most of the points are still valid, specially the performance impact.