Java™ Performance

Footnotes

Chapter 2

1 A 3.0 GHz processor executes 3 billion clock cycles per second.

Chapter 3

1. On Java 7 Update 4 and later HotSpot VMs, -XX:+UseParallelOldGC is ergonomically selected as the default garbage collector for server class machines. -XX:+UseParallelOldGC also enables -XX:+UseParallelGC.

Chapter 6

1. java.util.concurrent.ConcurrentHashMap was introduced in the Java 5 SE class libraries and is available in Java 5 and later Java JDKs/JREs.

Chapter 7

1. The actual size allocated by the HotSpot VM may be slightly adjusted depending on the memory system of the hardware platform and the operating system. This is true of all the command lines listed on this page.

2. “ParNew GC” is explicitly enabled using -XX:+UseParNewGC. It is automatically ...