Updated garbage collection

Garbage collection has been one of Java's great claims to fame. In Java 9, the Garbage-First (G1) garbage collector is now the default garbage collector on both 32- and 64-bit servers. In Java 8, the default garbage collector was the parallel garbage collector. Oracle reports that there are three garbage collection combinations that will prohibit your application from starting in Java 9. Those combinations are:

• DefNew + CMS
• Incremental CMS
• ParNew + SerialOld

We will take an in-depth look at Java 9 garbage collection in Chapter 7, Leveraging the New Default G1 Garbage Collector.