A big part of Java's goal to be platform-independent, it means "Write Once, Run Anywhere". WORA is the number one selection criterion for adopting Java technology among IT and IS professionals, so says the Java homepage.

WORA stands for "Write Once, Run Anywhere" and is a trademark of Sun Microsystems meant to convey the idea that Java programs, once written, can be run on any platform.

An alternate and disparaging parody form of the acronym is "write once, run away". This one is not trademarked as far as I know.