jLuger.de - @Override and Interfaces in Java 6

Today I've checked out a colleagues modules and got right away a compile error. It was complaining that a method was not overriding a method in any superclass. First I thought this error was caused due to some changes in the library the class was based on. But the colleague told me that he had checked in the latest version of the code and the used libraries. While I was at his workplace to ask him some details about his module he showed me the code in the IDE and there were no error markers but it was the absolutely same code that I had.
So I've took a closer look and it turned out that the method in question was implementing an interface method. So googling for "java interface override" brought me to Stackoverflow. In a comment to the answer there was a hint that the semantic of @Override annotation has changed. In Java 6 it is allowed to annotate methods that implement an interface while it is forbidden in Java 5. So checking the compile options it turned out that my colleague had Java 6 while I had Java 5 enabled. After I adjusted my compile settings to Java 6 everything worked fine.