The CLDC java.lang package is a subset of the J2SE java.lang package. Perhaps the most notable omissions compared to J2SE are floating point operations and, in particular, floating point (Float) and double precision (Double) classes. These omissions have implications to all other classes if floating point is used.

When compared with J2SE v1.3 API, there are several other classes that are omitted from the CLDC API, including ClassLoader, Compiler, InheritableThreadLocal, Number, Package, Process, RuntimePermission, SecurityManager, StrictMath, ThreadGroup, ThreadLocal, and Void.

We describe the main classes available in the CLDC java.lang package in the tables on the next few panels. The use of each of these classes should already be familiar to any Java developer.

In addition to these core classes, you will also see that the Runnable interface is supported by CLDC, as are the Exception, Error and related classes.