next up previous
Next: ``Different Computers Use Different Up: Write Once, Run Anywhere: Matters Previous: Write Once, Run Anywhere: Matters

What ``Write Once, Run Anywhere'' Means

  From the beginning, Sun intended Java to be a platform-neutral language. That is, Java programs would be written to run on a Virtual Machine instead of a physical computer. The virtual machine, then, would run on a real computer. Because Java's Virtual Machine has to strictly adhere to interface and behavior definitions, a programmer can develop a program for the Java Virtual Machine on the sort of computer that he likes, and expect it to run on the sort of computers that his customers like, inside of their Java Virtual Machines.

This means that when you go to the store to buy an application, you don't buy the ``Mac version'' or the ``Windows version.'' You buy the ``Java version.'' And as long as you have the Java Virtual Machine--which is free, and available from a large number of vendors--you can buy the program without having to worry whether it's going to run on your computer.

Matt Curtin