When it's a power of 2 keep in mind that you can use a simple and fast shift expression: 1 << exponent

For example:

2² = 1 << 2 = (int) Math.pow(2, 2)
2¹⁰ = 1 << 10 = (int) Math.pow(2, 10)

For larger exponents (over 31) use long instead:

2³² = 1L << 32 = (long) Math.pow(2, 32)

BTW, in Kotlin you have shl instead of <<:

(Java) 1L << 32 = 1L shl 32 (Kotlin)

Another implementation with O(Log(n)) complexity

public static long pow(long base, long exp){        
    if(exp ==0){
        return 1;
    }
    if(exp ==1){
        return base;
    }

    if(exp % 2 == 0){
        long half = pow(base, exp/2);
        return half * half;
    }else{
        long half = pow(base, (exp -1)/2);
        return base * half * half;
    }       
}