JVM tuning

JVM tuning is an operation that should be done after performance tests or during production. JVM configuration affects the Java application's performance. There are two necessary configurations:

• Memory settings (such as heap configuration)
• Garbage collector settings

There are a lot of publications about JVM tuning. Thus, in this recipe, we will only mention the main aspects.

How to do it…

Every JVM setting can be set in JAVA_OPTS (Java Environment Options). A great place to do it is in the ${TOMCAT_HOME}/bin/setenv.sh file.

First, let's set a proper garbage collector. The best option for portal systems is Concurrent Collector or G1 (in Java 8). These garbage collectors perform most of their work concurrently with only a small period of stop-the-world time. These garbage collectors give the best performance. The typical setting is as follows:

JAVA_OPTS = "$JAVA_OPTS -XX:+UseParNewGC -XX:+UseConcMarkSweepGC 
-XX+CMSParallelRemarkEnabled -XX:ParallelGCThreads=8 
...