New to Java

Hi, i am trying to make an static final array which holds the key for answer on a test. the answers are all letters. so i am trying to make an array but i get an error when i try to compile saying "] expected" and it highlights the last line where i try assigning the char 'B' to the first box of the array. any comments or suggestions ? thanks.

public class DriverExam
{
    public final int KEYNUM = 20;
    public final char[] KEY = new char[KEYNUM];
    
    KEY [0] = 'B';
    

} // end class DriverExam