Performance considerations related to Java include the size of the Java heap, whether JIT (Just In Time compiler) is enabled, and whether client applications are using persistent connections.
If your system requires large numbers of connection manager threads you might need to increase the heap size to improve performance; but see Memory use increases over time for information about potential problems if the heap size is too large. For more information, see Configuring Java shared classes.
System environment statistics are available to show the following Java statistical information:
Use the java -version command to find whether the JIT is enabled; it is enabled by default. Immediately after a CICS Transaction Gateway starts, performance might be relatively slow because of JIT overheads. See your JVM documentation for information about JIT techniques.
Performance is better if you flow multiple requests using the same JavaGateway object than if you create a JavaGateway object with each request. Whenever you create and destroy a new JavaGateway object you use additional system resources for creation and destruction of the object itself, creation and destruction of any associated sockets, and garbage collection.