Intern strings generated by Wicket that have bigger chance to be duplicated

I've been doing some performance measurements recently and I've noticed that Wicket produces some higher number of String objects like:

• small numbers ("1", "2", "3", ...) generated from repeaters' String.valueOf(nextId)
• HTML element names/attributes ("span", "div", ...) generated in XmlTag#getName, #getAttribute, ...

We can reduce memory usage for those by using String#intern().
Since Java 7 the interned strings are stored in the Heap memory so this won't affect negatively the perm generation.
Interned strings are GC-ed so this is also not a concern.

http://java-performance.info/string-intern-in-java-6-7-8/ provides good explanation how to avoid the CPU penalty caused by String#intern() if needed.