jmap:tldr:76ca3

The command "jmap -histo ${java_pid}" is used to generate a histogram of the Java heap memory on a running Java process with the specified process ID (java_pid).

Here is a breakdown of the different parts of the command:

• "jmap" is a command-line tool that is bundled with the Java Development Kit (JDK). It is used for troubleshooting and monitoring Java applications, particularly their memory usage.
• "-histo" is an argument or option that is passed to the "jmap" tool. It instructs "jmap" to generate a histogram of the objects in the Java heap memory. The histogram represents the number of objects of each type present in the heap.
• "${java_pid}" is a placeholder for the process ID of the Java application you want to inspect. You need to replace it with the actual process ID before running the command.

By executing this command, you will get a tabular representation of the objects in the Java heap memory. The table will include columns like the count, size, and fully qualified name of each object type. This information can be useful for diagnosing memory leaks or understanding the memory usage patterns of a Java application.