jps：
--j ps is the process used to view hotspot virtual machines that have access.
jstack ：
- Print out the Java stack information for the given java process ID or core file or remote debugging service.
jstat ：
- For monitoring HotSpot-based JVMs.
jstatd ：
- is an RMI-based service program that monitors the creation and destruction of resources in the HotSpot-based JVM, and provides a remote interface to allow remote monitoring tools to connect to the local JVM to execute commands.
jmap：
——A tool for outputting all objects in memory, which can output the heap in the VM into text in binary.
jhat：
- Tools for offline analysis of the JAVA heap.
jConsole：
- JVM operation monitoring tool, which can monitor memory, threads, etc.
VisualVM：
——Developed based on NetBeans platform, it has the feature of plug-in extension function, through the extension of plug-in, it can be used to display virtual machine process and process configuration and environment information (jps, jinfo), monitor CPU, GC, heap, Method area and thread information (jstat, jstack), etc.