It differs from language to language. Java was designed for "write once, run anywhere" - which includes in the future. They have been very careful -- too carefu

It differs from language to language. Java was designed for "write once, run anywhere" - which includes in the future. They have been very careful -- too careful, some would argue -- to keep backwards compatibility. Other languages don't care about that so much, preferring evolving rapidly. Unfortunately, it's not something you can predict. Also, compilers change, sometimes introducing bugs of their own, sometimes fixing bugs that the software relied on. A program doesn't exist in a vacuum.