How to Resolve \'java.lang.OutOfMemoryError: GC Overhead Limit Exceeded\' in Java?

Resolving "java.lang.OutOfMemoryError: GC Overhead Limit Exceeded" in Java

When working with large datasets involving numerous HashMap objects, developers may encounter the "java.lang.OutOfMemoryError: GC Overhead Limit Exceeded" error. This error signifies that the garbage collection (GC) process is consuming an excessive amount of time, hindering the efficient operation of the program.

To mitigate this error, two command-line arguments can be employed for the Java Virtual Machine (JVM):

• Increasing the Heap Size: Using "-Xmx1024m" allocates more memory to the heap, providing more space for object storage and reducing the likelihood of the error.
• Disabling the GC Overhead Check: "-XX:-UseGCOverheadLimit" suppresses the error check altogether, but may lead to the heap running out of memory if allocation attempts continue unchecked.

While these command-line options can be effective, there are additional programmatic alternatives to address this issue:

1. Specify a Smaller Heap Size:

Attempt using a smaller heap size, such as "-Xmx512m", which may mitigate the problem while still providing sufficient memory.

2. Manage Batch Processing:

Divide the HashMap objects into smaller batches and process them incrementally rather than handling them all at once. This reduces the memory consumption at any given time.

3. Use String.intern():

If there are numerous duplicate strings in the HashMaps, use String.intern() to create and retrieve canonical representations of those strings. This ensures that only one instance of each string exists, reducing memory usage.

4. Tune the HashMap Constructor:

Use the HashMap(int initialCapacity, float loadFactor) constructor to initialize HashMaps with an appropriate initial capacity and load factor for your specific use case. This helps manage memory allocation and reduce the likelihood of collisions.

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