Using the hex literal directly seems simpler than either of the approaches you state, although they all have the same effect.
public class Test {
public static void main(String[] args) {
String op = "\u221A";
char operator1 = op.charAt(0);
char operator2 = '\u221a';
char operator3 = 0x221a;
System.out.println(operator1 == operator2);
System.out.println(operator2 == operator3);
}
}