Monitoring Tools

The tools listed in the Table 2-4 are designed for monitoring applications that are running.

The release of JDK 8 introduced Java Mission Control, Java Flight Recorder, and jcmd utility for diagnosing problems with JVM and Java applications. It is suggested to use the latest utility, jcmd instead of the previous jstack, jinfo, and jmap utilities for enhanced diagnostics and reduced performance overhead.

Table 2-4 Monitoring Tools

Tool or Option	Description and Usage
Java Mission Control	Java Mission Control (JMC) is a new JDK profiling and diagnostic tools platform for HotSpot JVM. It s a tool suite basic monitoring, managing, and production time profiling and diagnostics with high performance. Java Mission Control minimizes the performance overhead that's usually an issue with profiling tools. See Java Mission Control.
jcmd utility	The jcmd utility is used to send diagnostic command requests to the JVM, where these requests are useful for controlling Java Flight Recordings. The JFRs are used to troubleshoot and diagnose JVM and Java Applications with flight recording events. See The jcmd Utility.
Java VisualVM	This utility provides a visual interface for viewing detailed information about Java applications while they are running on a Java Virtual Machine. This information can be used in troubleshooting local and remote applications, as well as for profiling local applications. See Java VisualVM.
JConsole utility	This utility is a monitoring tool that is based on Java Management Extensions (JMX). The tool uses the built-in JMX instrumentation in the Java Virtual Machine to provide information about performance and resource consumption of running applications. See JConsole.
`jmap` utility	This utility can obtain memory map information, including a heap histogram, from a Java process, a core file, or a remote debug server. See The jmap Utility.
`jps` utility	This utility lists the instrumented Java HotSpot VMs on the target system. The utility is very useful in environments where the VM is embedded, that is, it is started using the JNI Invocation API rather than the `java` launcher. See The jps Utility.
`jstack` utility	This utility can obtain Java and native stack information from a Java process. On Oracle Solaris and Linux operating systems the utility can alos get the information from a core file or a remote debug server. See The jstack Utility.
`jstat` utility	This utility uses the built-in instrumentation in Java to provide information about performance and resource consumption of running applications. The tool can be used when diagnosing performance issues, especially those related to heap sizing and garbage collection. See The jstat Utility.
`jstatd` daemon	This tool is a Remote Method Invocation (RMI) server application that monitors the creation and termination of instrumented Java Virtual Machines and provides an interface to allow remote monitoring tools to attach to VMs running on the local host. See The jstatd Daemon.
`visualgc` utility	This utility provides a graphical view of the garbage collection system. As with `jstat`, it uses the built-in instrumentation of Java HotSpot VM. See The visualgc Tool.
Native tools	Each operating system has native tools and utilities that can be useful for monitoring purposes. For example, the dynamic tracing (DTrace) capability introduced in Oracle Solaris 10 operating system performs advanced monitoring. See Native Operating System Tools.