In general, none of the Java programming language core API classes are supported in the Java Card platform. Some classes from the java.lang package are supported (see Section 2.2.2.4, **Class**es), but none of the rest are. For example, classes that are not supported are String, Thread (and all thread-related classes), wrapper classes such as Boolean and Integer, and class Class.

Class java.lang.System is not supported. Java Card technology supplies a class javacard.framework.JCSystem, which provides an interface to system behavior.