How do I create an applet that loads in a 1.1 browser from the 1.4 JDK?

The 1.4 JDK creates class files that are incompatible with the 1.1 runtime. Prior versions of the JDK defaulted to the old version. 1.4 defaults to the new (1.2) format. To generate an applet compatible with the old VM, compile with the -target option, as in:

javac -target 1.1 HelloWorldApplet.java