How to deal with "java.lang.OutOfMemoryError: Java heap space" error?

"java.lang.OutOfMemoryError: Java heap space" means that the application has exhausted the maximum heap space. To fix this error, you can try the following:

1. Increase the maximum heap size by specifying the -Xmx option when starting the JVM. For example, you can start the JVM with -Xmx2g to increase the maximum heap size to 2 GB.

2. Decrease the amount of data that the application stores in the heap. This can be done by optimizing the code to use less memory, such as using data structures with a smaller memory footprint or reducing the number of objects that are created.

3. Use a tool like jmap or jvisualvm to identify what is consuming the most memory in the application. This can help you understand what is causing the memory usage to increase and allow you to optimize the code accordingly.

4. If the application is using a lot of third-party libraries, consider using a tool like ProGuard to shrink and optimize the code. This can help reduce the overall memory usage of the application.

5. If the above steps don't help, consider using a 64-bit JVM, as it can address more memory than a 32-bit JVM.