Stack Space

[Will Myers]

I have been asked to find out how much stack space a function will use and have no idea how to do this, any pointers? The function is:

public long getSumOfNaturalNumbers(long num) {

		return num * (num + 1) / 2;

	}

[Will Myers]

I have done some research and have come up with:

long = 64 bit * 2,
int = 32 bit * 2,

so 192 bits or 24 bytes on the stack total, is this correct? It's assuming the return and param are not counted....

[fred rosenberger]

I don't think so...More than just the variables are stored in the stack, but I don't think you can find out what exactly. It may even be dependent on which exact implementation of the JVM you are using.

A better answer would be "Why does it matter?"

[Mike Simmons]

The javap tool can tell you this, using the -verbose option. At least, it can tell you about what the compiled class file says the stack usage should be. It's possible for HotSpot to modify this at runtime, I suppose. But I doubt it will change too much. Unless you use the funky JVM options like -XX:+DoEscapeAnalysis.