VisualVM (Visual Java Profiler) is a powerful and versatile tool used for profiling, monitoring, and analyzing Java applications. It is an official part of the Oracle JDK and is available as a standalone application or as a plugin for the NetBeans IDE.

VisualVM provides a graphical user interface that allows developers and system administrators to inspect various aspects of Java applications running on the Java Virtual Machine (JVM). Some of the key features of VisualVM include:

1. Profiling: VisualVM allows you to profile Java applications, which means you can gather information about the application’s memory usage, CPU usage, thread behavior, and other performance-related metrics. This is useful for identifying performance bottlenecks and memory leaks in your application.
2. Monitoring: With VisualVM, you can monitor the behavior of Java applications in real-time. It provides real-time graphs and statistics for various JVM and application-level metrics, helping you understand the application’s behavior during runtime.
3. Thread Analysis: VisualVM allows you to inspect and analyze the threads running within your Java application. You can identify thread contention, deadlocks, and thread-related performance issues.
4. Heap Dump and Memory Analysis: VisualVM allows you to take heap dumps of Java applications, which capture the memory state of the application at a specific point in time. These heap dumps can be analyzed to identify memory leaks and understand memory usage patterns.
5. Plugins: VisualVM supports a plugin system that enables integration with other profiling and monitoring tools. Various plugins can extend the functionality of VisualVM to support different types of applications and use cases.