You can check which Java version is on your Mac to see if you have the most up-to-date Java running, or you can check on the Java website.

To do the same, open Command Prompt and then run the following command to check which version of Java is installed on your computer.

But these aforementioned Java command-line tools -- namely, javac, javap, jstat, jdeps and jar -- are the five that serious software developers need to know.