Computer Science

Faculty of Engineering, LTH

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Java-based platform

Lund Java-based Real-Time (LJRT) library

The LJRT Java2C translation system is now hosted at where you can find the source code for the cs realtime classes.

Note: The term Java-based that is due to the fact that our way to accomplish a J2SE-compatible (any embedded program will for sure run on any Java-enabled desktop, which is more standard Java than J2ME or a RTSJ will provide) is not compatible with the Java license conditions from Sun (we provide a real-time improved J2SE subset affecting the RTOS API without going via the JCP and without requiring a JVM). Thus, we may not call our free solution "Java", so we call it Java-based (again, this is legally not Java).


  1. JThread class resembling RTThread in terms of the available methods, but the former is for concurrency the Java way whereas the latter is for  real-time execution (when cross compiled and run on top of an RTOS).
  2. The RTThread is extended with checking and exceptions for missed deadlines, also in the case of soft real time (on a JVM).
  3. Both JThread and RTThread provide cross-thread exception handling via event listeners, etc.
  4. The time may refer to virtual time, which stops when the JVM is suspended due to, e.g., a breakpoint in a debugger (such as eclipse). That is, even real-time threads can be debugged conveniently.
  5. The RTEventBuffer implements the RTEventBufferInput and RTEventBufferOutput interfaces, and has the ownership functionality for events. Some methods are final for efficiency in cross-compiled applications.
  6. Both virtual real-time support and other real-time system properties are collected in a class RTSystem.
  7. etc. etc.