If you don't want to mess with a StringBuffer, you can use the indexOf() and substring() methods of String. Like this:
substring(int,int) takes the first and last index of the string and creates a new substring of it. So if you find the indexOf() the "(" and ")" and pass those ints to substring(int,int), you'll create the proper substring. But you have to +1 to the first index so you won't include the "(".