Understanding and Resolving java.lang.OutOfMemoryError: GC Overhead Limit Exceeded

java.lang.OutOfMemoryError: GC overhead limit exceeded is thrown by the JVM when garbage collection becomes extremely inefficient, indicating that the program spends about 98% of its time performing GC but recovers less than 2% of heap memory, often repeatedly.

The JVM may also alternately throw java.lang.OutOfMemoryError: Java heap space , and both errors can appear in the same application.

Typical causes include:

Traffic surge : a sudden increase in requests creates many objects, exceeding the allocated heap.

Memory leaks : code retains references to objects that are no longer needed, causing the heap to fill up.

Insufficient heap size : the configured -Xmx value is too small for the workload.

Inefficient code : frequent creation of temporary objects inside loops, e.g., new Object() , overwhelms the GC.

GC algorithm limits : algorithms such as CMS may struggle with severe fragmentation.

To resolve the error you can:

Fix memory leaks and eliminate unnecessary object retention.

Increase the heap size (e.g., set a larger -Xmx) while avoiding excessive allocation that could cause long GC pauses.

Adjust the GC algorithm, for example switch to G1GC with -XX:+UseG1GC and limit Full GC pauses using -XX:MaxGCPauseMillis=200 .

Investigation steps (two‑step process):

Capture a heap dump : enable -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/opt/tmp/heapdump.bin so the JVM writes a heap dump when the error occurs.

Analyze the heap dump : use tools like Eclipse MAT to examine the dump and identify memory‑leaking objects or inefficient allocation patterns.