Optional: If you want to compile from the command line (which is not needed for the intro courses):.Add this action to step 3: Select J2SE 5.0 from the drop-down menu under 'Java Applet Runtime Settings'.Follow the directions above to ensure that your Mac has Java 1.5.Optional: If you use Safari and Java 1.5 applets are not displaying:.In the 'Java Application Runtime Settings Pane' drag J2SE 5.0 to the top of the list. Open the Java Preferences application in J2SE 5.0.If the J2SE 5.0 directory is missing, Download the latest Java 1.5.0 from Apple and install it.Look for the Java Preferences app on your Mac in Applications > Utilities > Java > J2SE 5.0 (cmd-shift-U opens Utilities).Depending on the age of your MAC, you may have Java 5 or 6 ('JDK 6.0_x'), either of which is fine.If it says something like 'javac 1.5.x' or 'JDK 5.0.x' or (where x is any number) you're done! Look under the compiler tab at the bottom right and check the version. Download the DrJava 'Current Stable Release' MacOS X app from and put the application in your Applications folder.