The Well-Grounded Java Developer, Second Edition

17 Modern internals

This chapter covers

• Introducing JVM internals
• Reflection internals
• Method handles
• Invokedynamic
• Recent internal changes
• Unsafe

Java’s virtual machine (JVM) is an extremely sophisticated runtime environment that has, for decades, prioritized stability and production-grade engineering. For these reasons, many Java developers have never needed to poke about in the internals, because it is simply not necessary to do so most of the time.

This chapter, on the other hand, is for the curious—the people who would like to know more, who would like to draw back the curtain and see some of the details of how the JVM is implemented. Let’s start with method invocation.

17.1 Introducing JVM internals: Method invocation

To get going, let’s ...