The real-time JRE provides a highly deterministic Java runtime environment that supports the unique requirements of real-time applications. It is a robust and compliant implementation of the Real-time Specification for Java (RTSJ) defined by JSR-1 (and soon JSR-282), and includes Apogee developed technologies that provide increased performance and hard real-time responses. Each RTJRE is based on either MJRE or CJRE and includes its standard Java APIs and features.

Each RTJRE includes the target-specific ports of the following components: IBM's J9 Virtual Machine (J9VM), extended by Apogee to support VM RTSJ features. Apogee's highly deterministic Just-Ahead-of-Time (JAOT) compiler based on IBM's JIT compiler technology. Apogee's Real-time Garbage Collector (RTGC) integrated with the port of RT J9VM. IBM's Foundation Class Library (FCL) or Harmony Class Library (HCL) from Apache. Apogee's Real-time Java Class Library (RTJCL), compatible with: Realtime Specification for Java, defined by JSR-1.

RTSJ Java applications "application-level" packages (e.g. Log4J) "client-side" runtimes (e.g. Equinox) Real-time Class Library Foundation/Harmony Class Library J9+RT Java VM, RTGC, JAOT Linux/LynxOS x86/PowerPC

Support for the following JSR-defined standards is currently under development and will be available when their specifications are completed.

• Safety Critical Java (JSR-302).
  
• RTSJ version 1.1 (JSR-282).