[merb]

I understand to run Java 1.5, or better Java 1.6 but not 1.3 and 1.4 that's aweful. But I know that's a fact since I've used Apache Fop and they try to have a compatibility up to Java 1.3. For me I've writing all my software with the latest Java, but I don't care which os (even RHEL 5/6 would work, if they could get java 8 to run) Supporting everything down needs have so many more Lines of Code and is rareley harder to maintain / code. Especially Option Types and Java 9 + Java 10 brings your Java Code to a further level, I also don't get it why somebody would code a new project via J2EE if there are so many great servers like wildfly and netty.

[Alupis]

Well, a Java 1.3 application isn't going to be a new application - usually a legacy application which has a lot of custom libraries built specifically for that version of Java, and would require significant effort to bring the codebase up to date in terms of running on a modern platform. At my company, one of our most used internal applications runs on 1.3 - it's an application which allows user-made plugins, however we don't have the source for the main application, which means we're stuck maintaining a 1.3 system.

As an aside, J2EE is quite good and very prevalent in enterprise, JBoss, GlassFish, Tomcat, etc...