I've been experiencing a few problems when Firefox loads pages containing Java applets. I also know that others have had problems with Firefox loading PDFs.

The problem seems to be that Java and Acrobat can eat up huge amounts of memory that either crashes Firefox, or some 'other' operating system that people sometimes use. Of course, it never crashes GNU/Linux.

To fix this, the amount of memory given over to these programs should be limited. The way to do this is as follows.

Entering

about:config

in the address bar in Firefox gives a list of config options. The option

browser.memory.cache.enable

should be set to 'true'. You can toggle it by right-clicking it.

Then, the option

browser.memory.cache.capacity

should be created, if it doesn't exist. To do this right-click on the window displaying the preferences. Select 'New>Integer'. In the dialogue box enter:

browser.memory.cache.capacity

In the next, dialogue box enter a sensible value, like for example 8192, depending on how much RAM you have.

For me this has fixed the problem.