import java.math.BigInteger;
BigInteger num1 = new BigInteger("someNumber");
BigInteger num2 = new BigInteger("someNumber");
BigInteger result = num1.multiply(num);
BigInteger int1 = new BigInteger("131224324234234234234313");
BigInteger int2 = new BigInteger("13345663456346435648234313");
BigInteger result = int1.multiply(int2)