Java character array initializer

Here's how you convert a String to a char array:

String str = "someString"; 
char[] charArray = str.toCharArray();

I'd recommend that you use an IDE when programming, to easily see which methods a class contains (in this case you'd be able to find toCharArray()) and compile errors like the one you have above. You should also familiarize yourself with the documentation, which in this case would be this String documentation.

Also, always post which compile errors you're getting. In this case it was easy to spot, but when it isn't you won't be able to get any answers if you don't include it in the post.