Showing posts from November, 2012

Create new Java Class files at runtime

When we write programs usual method is to write all the code compile it and run. But when we try to complex things some times we may want to generate a new class and use it at runtime. As an example I wanted to create a class which parse a xml message and create a new Java object from that data. This is used in web server. So that result object varies according to the web service which is deployed. The solution was to inspect the service at deployment time and create a new parser class according to that in the service deployment time. It has to be noted that this parser had to be generated as a .class file and dynamically added to the classpath. So the result was to use a bytecode manupulation library. There are few bytecode manuplulation libraries available as ASM and JavaAssist.
I used JavaAssist for this. The reason for using JavaAssist is it is simple to create a new class from the scratch using JavaAssit. When we create new class files using JavaAssit we have to create all the…