What is a CAP file?

Julien SIMON

The CAP file format is defined by the Java Card 2.1.1 Virtual Machine Specification.

A CAP file is the loading unit in Java Card. Using a host tool called converter, a CAP file must be built for each package that will be loaded on the card: it will contain all classes and interfaces belonging to the same package.

Although CAP means "converted applet", a CAP file doesn't necessarily contain an applet. If the corresponding package is a simple library (i.e. it only defines an API), there won't be any applet inside the CAP file…