Find the largest palindrome made from the product of two 3-digit numbers. (Java)

Question

I am having a bit of trouble solving Project Euler question 4. I am inexperienced in programming and didn\'t really understand other answers. I managed to write a code that

Answer 1

for 3 digits loop can be started from 100 to 1000(exclusive).

You can try this ::

int num1 = 0, num2 = 0;
for(int i=100; i<1000; i++){
    for(int j=100; j<1000; j++){
        String mul = String.valueOf(i*j);
        if(isPalindrome(mul)){
            num1 = i;
            num2 = j;
        }
    }
}
System.out.println(num1*num2);

Implement palindrome method as :

boolean isPalindrome(String str) {
    String strRev = new StringBuilder(str).reverse().toString();
    return str.equals(strRev);
}

This works good but take this as reference and improve as needed Thanks