Configuring the JVM

The JVM has lots and lots of configuration possibilities. In this book, we will focus on just a few, but these are the ones that, over the years, have proved most valuable in terms of information and performance-related impact.

Default settings

The Hotspot JVM is nowadays ergonomic. This means that, based upon the platform configuration, it will select the runtime compiler, heap configuration, and GC that, according to its documentation, will produce a good to excellent performance for most applications. To get the best possible performance, specific tuning might, however, still be required.

Starting up, JVM is already configured with a set of options. Some are just defaults, while others are dynamically, or ergonomically, set by JVM itself during startup and after the analysis, of, for example, the available hardware that the JVM is executing on. Lastly, a set of options, which by default can be of a static or dynamic nature, can be set as JVM arguments.

To find out about...