Ancient Java Programs
One cool thing about Java is that cross-platform compatibility is a fundamental concept to the language. “Write once run anywhere”, also known as WORA, is a key design feature of the language. It’s always been important since day one for Java to be cross platform.
This may be the reason why Java is known for being resource-hungry — it requires a JVM to execute a program.
However, this does mean that Java programs are quite resilient to the test of time. For the most part you can pull down an ancient .jar file, run it, and it will work.
Here are some examples: