Java.Multithreading.What is the JVM startup parameter used to control the size of a thread stack?

🔍 In the Java Virtual Machine (JVM), you can control the size of each thread’s stack using the following startup parameter:

---

✅ -Xss<size>

This option sets the stack size per thread.

---

💡 Example:

java -Xss512k MyApp

This sets each thread’s stack size to 512 KB.

---

📐 Common Sizes:

Value	Meaning
-Xss256k	256 kilobytes
-Xss1m	1 megabyte
-Xss2m	2 megabytes

---

🧠 Why It Matters:

• Too small: You’ll get a StackOverflowError in deep recursions or heavily nested calls.
• Too large: You may run out of memory quickly, especially with many threads.

📌 Default Size:

The default depends on:

• OS
• Architecture (32-bit vs 64-bit)
• JVM implementation

Typical defaults:

• ~1 MB on most 64-bit JVMs
• ~512 KB on 32-bit JVMs

You can check it using tools like jstack or estimate by spawning threads until OOM.