I have few overloaded method, which I can replace with vararg, but these are getting called numerous times.
I just wanted to know its impact. I assume jvm creates an array from the parameters at runtime, so theoretically there must be some impact, not sure practically will it impact or not!
The one and only answer that makes sense here: go and measure yourself. Yes, you are correct - varargs are syntactic sugar - and the compiler creates arrays under the hood. So, yes - there is a certain performance impact.
But if that penalty really matters to you depends solely on your requirements and your context.
I think (opinion) here: when this really impacts the perceived performance of your application - then you probably have other problems already.