Research And Development Of Real-time Middleware Based On Java

With the constant development of internet technology, Java application on the distributed systems and the application of real-time more and more extensive. But common Java platform, Java Virtual Machine's garbage collector from time to time to start running can not guarantee real-time systems and implementation of real-time predictability of the requirements, Affect the application of Java in real time system. Java can construct real-time system by implementing RTSJ (Real-time Specification for Java) which can enhance openness of Java. However, to implement the RTSJ, support from operating system, Java runtime environment and Java develop kit are essential. It is not suitable for common Java platform to develop real-time system. The real-time middleware to resolve the real-time problem on common Java platform for distributed applications is an effective way.This paper mainly research Java applied to soft real-time systems the common platform for the Java Virtual Machine under the occasional garbage collector start-up problems, proposed a periodic upgrading the priority of GC . Approach is: First, the priority was divided into two levels by task's importance: the critical threads and non-critical threads, set up ahead of the priority of the task, In the garbage collection by calculating the time that the garbage collection cycles to calculate the maximum time T_GC. In the task to run the longest period of time not exceeding T_GC raise the priority of non-critical thread to the maximum, so that the virtual machine memory not to be able to achieve the saturation level without affecting the critical tasks .Theoretical analysis and experimental results indicate that the components which be developed in this paper can set up ahead of the priority of the task, and then by calculating the garbage collection time, the task is running the longest period of time not exceeding TGC raise the priority of GC ahead of schedule GC, so GC does not affect the key threads in the circumstances be able to advance garbage collection in memory, so that the virtual machine's memory not reach the degree of saturation can improve the real-time performance of Java critical threads and the predictability of running under the general environment.