There will be always a downward compatibility. You can run your JDK 1.3 on JDK 1.5. However, many of the older functionalities have been deprecated in new releases and probably you need to use appropriate runtime parameters to compile and run JDK 1.3 code on higher versions.
Originally posted by Mani vannan: -- You have JDK 1.3 for development. Using that, how will you develop code with all features of JDK1.5? --
You won't, obviously - otherwise there wouldn't be a need for the existence of JDK1.5.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
We don't know what the intent of the question was. Interview questions don't necessarily have an answer, or just a single "correct" answer. It may have been asked to get the interviewee to speculate about options, and see what kind of approaches he might come up with.
This is a simple question. The interviewer asked this question to your friend to check his/her confident. The answer is already written by some guys.
We can try to compile jdk 1.3 in jdk 1.5 and some deprication warnings can come but the reverse is not true. We can not compile the jdk1.5 specific things in jdk 1.3. back compartibility is there but reverse is not possible. Dont confuse, the answer is no- we can do in that way.
There are some features in 1.5 (and 1.4) that you could approximate with 3rd party libraries ... concurrent package and regular expressions come to mind. Truly new language features like generics, autoboxing, enhanced for and such you couldn't fake with normal tools.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi
Java 5 generics grew mainly from Gilead Bracha's work on the GJ compiler (based on other earlier work on the Pizza compiler) with which you could do generics in whatever JVM was current at the time. This was long enough ago that I'm sure it ran under 1.3, and probably 1.2.2.
I wrote a little database engine using GJ, some years ago. Memories...
Maybe the interviewer was looking for a real old timer!