I've just realized an additional point. Owing to evolution of interfaces that are included in the JDK, such as JDBC, there are projects such as Hibernate which *cannot* be compiled with JDK 6, and must use JDK 5 (because JDK 6 added methods to interfaces). So, yes, there's significant benefit in retaining Java 5 until its End of Service Life.
I've just realized an additional point. Owing to evolution of interfaces that are included in the JDK, such as JDBC, there are projects such as Hibernate which *cannot* be compiled with JDK 6, and must use JDK 5 (because JDK 6 added methods to interfaces). So, yes, there's significant benefit in retaining Java 5 until its End of Service Life.