Abstract: Techniques for checking in JAVA™ computing environments are disclosed. The techniques can be used by a JAVA™ virtual machine to efficiently perform type checking. A JAVA™ class hierarchy which represents the hierarchical relationship of parent classes of JAVA™ class can be implemented as an array of class references. The array of class references can be used to efficiently perform type checking in JAVA™ computing environments. As a result, the performance of JAVA™ virtual machines, especially those operating with limited resources, is significantly enhanced.

Abstract: Improved techniques for storing and retrieving field descriptors in Java computing environments are disclosed. The techniques can be used to implement garbage collection for Java programs in a manner that is more efficient, especially for systems with limited resources (e.g., embedded systems). A reference identifier suitable for use by a Java virtual machine is disclosed. The reference identifier is associated with a Java object and can be stored in the internal class representation associated with the Java object at load time. Moreover, the reference identifier can be used at runtime to quickly determine whether a field of the associated Java object is a reference to another Java object. As a result, the amount of processing conventionally performed at runtime is reduced. This, in turn, can improve the runtime performance of Java virtual machines, especially those operating with limited resources (e.g., embedded systems).