This article, by David F. Bacon of IBM research, describes a garbage collector for Java which works with realtime systems.
Called Metronome, this new technology has already been adopted for use in the Navy’s new DDG-1000 destroyer, currently under development and scheduled for launch early in the next decade. At IBM, we are using Metronome as the underlying technology for a meter-scale helicopter called the JAviator, for which we’ve conducted initial flight tests. Since music is one of the most demanding realtime applications (the human ear is incredibly sensitive), we’ve also built a Java-based music synthesizer with response times of five milliseconds - as good as those achieved by hardware synthesizers.