$ cat lal.java
class Lal {
  public static long powpow(long x, long n) {
    return (long) Math.pow(x, n);
  }

  public static void main(String[] args) {
    System.out.println(powpow(-11, 9));
  }
}
$ javac lal.java
$ java Lal
-2357947691