1. Native profilers provide visibility into both the JVM code and the application
2. If a native profiler shows that time in GC dominates the CPU usage, then tuning
the collector is the right thing to do. If it shows significant time in the compilation
threads, however, that is usually not affecting the application's performance.
Java Mission Control
The commercial releases of Java 7 (starting with 7u40) and Java 8 include a new monitoring
and control feature called Java Mission Control. This feature will be familiar to users of JDK
6-based JRockit JVMs (where the technology originated), since it is part of Oracle's merging
of technologies for Java 7. Java Mission Control is not part of the open-source development
of Java and is available only with a commercial license (i.e., the same procedure as for com-
petitive monitoring and profiling tools from other companies).
The Java Mission Control program ( jmc ) starts a window that displays the JVM processes on
the machine and lets you select one or more processes to monitor. Figure 3-8 shows Java
Mission Control monitoring an instance of the GlassFish application server.