How do I migrate Struts from 2.0 to 2.5?

A lot of things have changed since Struts 2.0 (10 years).

They are all described in the release notes of each version , which you should read.

The best shot you have is to cast your 2.0 project to 2.3 alone (latest version which is currently 2.3.32).

The biggest things you need to refactor ( 2.0 to 2.3.32 ):

• remove DMI (this will probably be the biggest one).
• remove Dojo plugin and tags
• remove access to static methods
• change filter
• change attribute id
  
  to attribute var
  
  in tags
• modify dtd
  
  xml files (struts.xml, validation files, etc.)

Once you have a full working 2.3 project, you can follow the official Struts 2.3 to 2.5 Migration Guide ..

Remember that while you were allowed to use Java> = 6 prior to Struts 2.3 ,
Struts 2.5 will only work in Java> = 7 .

Good luck.