What is the maximum of number of arguments for varargs in java?

Question

What is the maximum of number of arguments which can be used by a vararg in java ? I believe there should be some limit and it is not infinite.

Say

If you're ever passing anywhere close to that number of parameters (around Integer.MAX_VALUE) via var-args, then you're doing something wrong. – Medicate

@berry120 Although it is a somewhat theoretical question, it is not uninteresting. – Carbonation

Note that all answers that tell a number greater 64K are wrong, no matter how many upvotes they got. – Johnstone

@Johnstone Which answers? ;-) – Womanly

Answer 1

A method (including the static class initializer) can have at most 64k. If the arguments are such that they can be pushed with a single bytecode that is 1 byte long each, you can have something about 64000 arguments on a call.

Johnstone

Ah! I didn't knew of that. Didn't took into consideration the method size actually. But I can't delete my answer, as it is accepted. :( Still I'll give you a +1. Thanks, I learnt something new. :) – Sanitary

@RohitJain No issues. I actually ran into this when I once tried to make a huge static array containing a parser table. I had to split the array initialization in different static initialization methods, but of course you can't split a method invocation.... – Johnstone

and what about main(String... params)? can i pass more parameters from the command line? – Manakin

@Manakin Probably yes, unless your shell doesn't support it. Nowadays the limits are loose, but I remember times when the usual space for command line arguments was 4k. But then it is no Java issue anymore in a strict sense. Should also be easy to test, just run a shell script that creates 100,000 files or so, and then run your java prog with argument * – Johnstone

@Johnstone "at most 64k" – can you elaborate? Is that some JVM specification limit or otherwise specified? – Womanly

MC emperor yes it is. – Johnstone

@Johnstone Could you provide a link to the specs? – Womanly

MC Emperor see the JVM spec, obtainable on the web. – Johnstone

A vararg is one array as an argument. – Competency

@PeterLawrey are you sure you understood the question and my answer? – Johnstone

By the way, variable arity parameter seems to be the technical name for varargs in the Java SE Specifications. But I could not find any details about limits. – Enrol