Why Java Throws StackOverflowError Instead of OOM in Single‑Threaded Scenarios

In the Java Virtual Machine specification, the JVM stack can trigger two kinds of errors: StackOverflowError when a thread requests a stack depth beyond the allowed limit, and OutOfMemoryError when the stack cannot be expanded due to insufficient memory. The native method stack behaves similarly.

The article presents a single‑threaded example using the VM argument -Xss128k that results in a StackOverflowError , demonstrating that in a single thread, memory allocation failures in the stack manifest as StackOverflowError rather than OOM.

It explains that multithreaded scenarios can lead to true OutOfMemoryError because each thread’s stack consumes a portion of the operating system‑limited process memory (e.g., 2 GB on 32‑bit Windows). Larger per‑thread stack sizes reduce the number of threads that can be created, increasing the chance of exhausting the remaining memory.

When OOM occurs due to too many threads, the usual mitigation is to reduce the maximum heap size ( -Xmx) and/or decrease the thread stack size, thereby freeing memory for additional threads.