public static long gcd(long a, long b)

// Java code to show implementation of
// gcd(long a, long b) method of Guava's
// LongMath class
  
import java.math.RoundingMode;
import com.google.common.math.LongMath;
  
class GFG {
  
    // Driver code
    public static void main(String args[])
    {
        long a1 = 14;
        long b1 = 70;
  
        // Using gcd(long a, long b) method
        // of Guava's LongMath class
        long ans1 = LongMath.gcd(a1, b1);
  
        System.out.println("GCD of " + a1
                           + " and " + b1
                           + " is " + ans1);
  
        long a2 = 23;
        long b2 = 15;
  
        // Using gcd(long a, long b) method
        // of Guava's LongMath class
        long ans2 = LongMath.gcd(a2, b2);
  
        System.out.println("GCD of " + a2
                           + " and " + b2
                           + " is " + ans2);
    }
}

GCD of 14 and 70 is 14
GCD of 23 and 15 is 1

// Java code to show implementation of
// gcd(long a, long b) method of Guava's
// LongMath class
  
import java.math.RoundingMode;
import com.google.common.math.LongMath;
  
class GFG {
  
    // Driver code
    public static void main(String args[])
    {
        long a = -5;
        long b = 15;
  
        try {
            // Using gcd(long a, long b) method
            // of Guava's LongMath class
            // This should throw "IllegalArgumentException"
            // as a < 0
            long ans = LongMath.gcd(a, b);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

java.lang.IllegalArgumentException: a (-5) must be >= 0