- Memory Management
- Asynchronous Event Handling
- Asynchronous Transfer of Control
- Asynchronous Thread Termination
- Physical Memory Access
- Minimum Implementations of the RTSJ
- Optionally Required Components
- Documentation Requirements
- Parameter Objects
- Java Platform Dependencies
Optionally Required Components
The RTSJ does not, in general, support the concept of optional components of the specification. Optional components would further complicate the already difficult task of writing WORA (Write Once Run Anywhere) software components for real-time systems. However, understanding the difficulty of providing implementations of mechanisms for which there is no underlying support, the RTSJ does provide for a few exceptions. Any components that are considered optional will be listed as such in the class definitions.
The most notable optional component of the specification is the POSIXSignalHandler. A conformant implementation must support POSIX signals if and only if the underlying system supports them. Also, the class RawMemoryFloatAccess is required to be implemented if and only if the JVM itself supports floating point types.