for-loop with multiple variable declarations

Question

I'm pretty sure the following is legal in Java

for (int var1 = 2, var2 = 3; var1 < 10; ++var1) {
  System.out.println(var1);
}

But when I try to run it in the Groovy console, I get this error

unexpected token: =

Are multiple variable declarations unsupported by Groovy or is there another reason why this isn't allowed?

Answer 1

It's a common gotcha for Java Developers. See this link for more detail:

Common gotchas you can use only one count variable.

Excerpts from the link:

for Loops

Another small difference is that you can’t initialize more than one variable in the first part of a for loop, so this is invalid:

for (int count = someCalculation(), i = 0; i < count; i++) {
   ...
}

and you’ll need to initialize the count variable outside the loop (a rare case where Groovy is more verbose than Java!):

int count = someCalculation()
for (int i = 0; i < count; i++) {
   ...
}

or you could just skip the whole for loop and use times:

someCalculation().times {
   ...
}