How to deal with multiple versions of Java

Reader Alex Wood had multiple versions of Java, and he asked if it was safe to remove some of these. So what is Java and why do you need so many versions?

Java is a platform that can run programs on a variety of hardware ­ not just personal computers, but phones, smartcards and other hardware and media such as printers, car navigation systems and Blu-ray discs. It can also run programs in a web page ­ such as games, chat rooms and so on ­ that can be accessed through any browser on Windows PCs, Macs, Linux and other hardware.

To run Java programs, you need the free Runtime Environment. It comes with a Control Panel item that, among other things, can check for updates at regular intervals. Each update is a full version rather than a patch, but updating does not remove previous versions.

So, sure enough, on checking my XP PC, in Add/Remove Programs, I had J2SE Runtime Environment 5.0 Update 5, and Java 6 updates 2, 3, 5, and 7, taking a total of 700MB of disk space. While not in Alex’s impressive storage league (1.6GB), this still struck me as excessive.

Then things got even messier. Checking the version on the Sun site revealed I was using Java 6 update 3, and the Java Control Panel on my PC stated I had version 6, update 6. Clearly things were a mess, so I downloaded and installed the current version ­ update 11. Both the website and the Control Panel now agreed I was using update 11, but I still had all the previous versions.

Searching on the Java website FAQ revealed that ‘you can safely remove older versions of Java from your system…’ and that ‘the latest available version is always compatible with the older versions’. However, in a blatant piece of bet-hedging, the next sentence reads ‘you can also keep older versions of Java installed, in case you have an applet/application that still depends upon a previous version’.

The Java Control Panel does provide the means to disable or remove runtime versions via the View buttons on the Java tab, but this doesn’t remove any files. So I made a System Restore point, and removed all but the latest update via Add/Remove programs.

So far, everything works as it should. Should you discover that some application or web page does need an old version, you can download and install these.

Installing the latest version of Java Runtime also gives you the opportunity to install the Yahoo Toolbar in your browser, so if you don’t want this make sure you untick the option. Should you miss this, and unwittingly install the Yahoo toolbar, then you can remove it by clicking on the pencil button on the toolbar, then Uninstall. This procedure works in both Internet Explorer and Firefox.

Another installation option is JavaFX. This was released last December and is a platform for creating ‘rich internet applications’ for the desktop and for mobile phones. You can find out more and see examples. If you want to find out if you have it, try a test.