Portability

Once Apple has written the interpreter and included it on their new system, it will be able to run all Java programs that already exist. Nothing new needs to be done with those programs.

Java programs are portable, which means that the same bytecode program can run on any computer system that has a Java interpretter. Also, a source program can be compiled into bytecodes on any computer that has a Java compiler. The source program does not have to be changed to meet the particular needs of various computer systems. No matter what computer you have, you can write the same Java programs.

This is unlike most other programming languages, where a different version of a program must be made for each variety of computer, and an executable program that runs on one type computer will not run on another.