While it has long been known that Apple would no longer actively support the Java Virtual Machine on Mac OS X, it was not necessarily clear that the Mac OS 10.7 Lion installer would uninstall the JVM supplied with previous releases of Mac OS 10. It appears, however, that that is the case, as users upgrading to Lion are left without a JVM.
Apparently the design going forward is for the OS to prompt the user to install the JVM when trying to run a Java application (such as Adobe’s applications which make use of the JVM). However as noted by Adobe this approach doesn’t appear to be bulletproof as some users are simply left with an application that won’t launch or an application that won’t close correctly.
Indeed, when I tried to log-in to a Juniper Networks SSL VPN that uses the “Host Checker” applet via Safari 5.1, the applet failed to run and no option was provided to install the JVM; attempting to log-in via Firefox resulted in a “missing plug-in” page, which resulted in the OS prompting me to download the JVM as designed.
If you think you may need to install the JVM for Mac OS 10.7, I suggest following Adobe’s suggested procedure:
- Go to Applications > Utilities > Java Preferences.
- Open the Java Preferences.
- If Java is not installed, you receive the following message:
“To open “Java Preferences,” you need a Java runtime. Would you like to install one now?”
- Click Install and accept the license agreement. The Java runtime is downloaded and installed.
Update: Users unable to get Lion to prompt them to install the JVM can download it manually from Apple.