Are String [] and String... (Var-args) same when they work internally?

Question

class WrongOverloading{
    void something(String [] a){ .. }
    Integer something(String... aaa){ return 1;}
}

Above code does not compile! Compiler says these are duplicate methods. So using String array or String var-args exactly mean the same?

How are they implemented internally?

Answer 1

They are effectively the same, except the compiler will not accept an varargs unless its the last argument and it won't allow you to pass multiple arguments to an array.

public void methodA(int... ints, int a); // doesn't compile
public void methodA(int[] ints, int a); // compiles

public void methodB(int... ints); // compiles
public void methodC(int[] ints); // compiles

methodB(1); // compiles
methodB(1,2,3,4); // compiles
methodC(1); // doesn't compile
methodC(1,2,3,4); // doesn't compile

Answer 2

From this SO discussion

The underlying type of a variadic method function(Object... args) is function(Object[] args). Sun added varargs in this manner to preserve backwards compatibility.

So, as every other answer has said, yes, they're the same.