Is there still a good reason to support JDK 1.4?

I'm looking at putting together an opensource project in Java and am heavily debating not supporting JDKs 1.4 and older. The framework could definitely be written using older Java patterns and idioms, but would really benefit from features from the more mature 1.5+ releases, like generics and annotations.

So really what I want to know is if support for older JDKs is a major determining factor when selecting a framework?

Understandably there are legacy systems that are stuck with older JDKs, but logistics aside, does anyone out there have a compelling technical reason for supporting 1.4 JDKs?

thanks,

steve

Is it possible that someone might want to use it on a Blackberry or similar mobile device? I don't believe they generally support 1.5.

We have customers who have only 1.4 installed (AS/400) and where it is an immense burdensome task to have a newer JVM installed. So, I am one of those who would consider Java 1.4 compatability important.

Note: This can most likely be achieved with Retrotranslator after compilation. You would then do all your tests both with a Java 1.5 with the original jars, and a Java 1.4 with the translated jars.

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JDK 1.4 went out of support from Sun back in Oct 2008. The only reasons I can think of why you should support your software running on an out-of-support JVM would be backwards compatibility and a customer base that still depended heavily on it.

I can't think of any technical reason to stick with 1.4 compatibility for mainstream Java with the possible exception of particular mobile or embedded devices (see discussion on Jon's answer). Legacy support has to have limits and 1.5 is nearly 5 years old. The more compelling reasons to get people to move on the better in my opinion.

Update (I can't sleep): A good precedent to consider is that [Spring 3 will require Java 5 (pdf)][1]. Also consider that the lot of the servers that the larger corporations are using are, or will soon be, EOL ( WAS 5.1 is out of support [since Sep '08][2], JBoss 4.0 support [ends Sep '09][3]) and that Java 1.4 itself is [out of support since Oct '08][4].


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I think it depends on what your project is. We have a client that still uses J2SE 1.4 (JRun, WebSphere 6).

While none of our clients are on J2SE 1.3, we have a few core components that we try to maintain J2SE 1.3 compatibility on (really basic, highly re-usable stuff).

That said, this may not be an issue. For our client, we were able to use some J2SE 1.5 compiled libraries by running the JAR/classes through [Retroweaver][1].


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