How to resolve the decrease in memory after using jmap -dump in the JVM?

Using the jmap -dump command in the JVM to generate a heap memory dump file may result in a decrease in memory, possibly due to the process of generating the dump file occupying a significant amount of memory or triggering garbage collection.

To address the issue of declining memory, you can try the following methods:

1. Adjusting JVM parameters: Increase the size of the heap memory by adjusting JVM parameters in order to accommodate the memory required to generate dump files.
2. Optimize garbage collection: If a decrease in memory is caused by triggering garbage collection, one can try optimizing the garbage collection strategy to reduce its frequency and duration, thus minimizing the impact on memory decrease.
3. Decrease the frequency of generating dump files: If the dump files are not needed frequently, consider reducing the frequency of generating dump files to minimize the impact on memory usage.
4. By using the -F option with jmap, it is possible to force the dump file generation, which may result in some performance loss but can prevent memory decline.

In general, different measures can be taken to address the issue of memory decline based on specific circumstances, adjustments and optimizations can be made according to actual situations.