What is an efficient way to compare StringBuilder objects

Question

Well I have two StringBuilder objects, I need to compare them in Java. One way I know I can do is

sb1.toString().equals(sb2.toString());

bu

Answer 1

A solution without new allocations would be to compare first at length, and if it differs, then char by char. This is more efficient and faster than performing a compare via a toString() on the StringBuilder call, which would allocate a new string.

The next snipped assumes both parameters aren't null neither the same object instance:

public boolean compare(final StringBuilder left, final StringBuilder right)
{
    final int length = left.length();

    if (length != right.length())
    {
        return false;
    }

    for (int index = 0; index < length; index++)
    {
        if (left.charAt(index) != right.charAt(index))
        {
            return false;
        }
    }

    return true;
}