Error Codes › java.lang.StackOverflowError

java.lang.StackOverflowError

COAL-013 · Stack overflow

Something called itself without stopping. How to read the repeating stack trace and find the data pack, script, or mod loop behind it.

What it looks like in the log

java.lang.StackOverflowError: null
	at com.example.somemod.Handler.process(Handler.java:88)
	at com.example.somemod.Handler.process(Handler.java:91)
	at com.example.somemod.Handler.process(Handler.java:91)

What it means

Java ran out of call stack, which in practice always means infinite recursion: something called itself, directly or in a loop, with nothing to end it. The giveaway is the stack trace - the same handful of lines repeat hundreds of times.

How to fix it

Read the repeating frames. The package name in the loop tells you which mod, data pack, or script owns the bug.
Data pack functions are a frequent cause: a function that calls itself, or two that call each other, with no condition to stop. Check anything added recently under datapacks/.
Automation and scripting mods loop the same way when one event triggers another - a block-break handler that breaks a block, for instance.
Raising -Xss is not a fix. A deeper stack only delays a genuine infinite loop. Find the recursion instead.