How to calculate the difference between two Java java.sql.Timestamps?

Question

Please include the nanos, otherwise it would be trivial:

long diff = Math.abs(t1.getTime () - t2.getTime ());

[EDIT] I want the most precis

Answer 1

Building on mmyers code...

import java.math.BigInteger;
import java.sql.Timestamp;


public class Main
{
    // 1s == 1000ms == 1,000,000us == 1,000,000,000ns (1 billion ns)
    public final static BigInteger ONE_BILLION = new BigInteger ("1000000000");
    public static void main(String[] args) throws InterruptedException 
    {
        final Timestamp t1;
        final Timestamp t2;
        final BigInteger firstTime;
        final BigInteger secondTime;
        final BigInteger diffTime;

        t1 = new Timestamp(System.currentTimeMillis());
        Thread.sleep(20);
        t2 = new Timestamp(System.currentTimeMillis());

        System.out.println(t1);
        System.out.println(t2);
        firstTime  = BigInteger.valueOf(t1.getTime() / 1000 * 1000).multiply(ONE_BILLION ).add(BigInteger.valueOf(t1.getNanos()));
        secondTime = BigInteger.valueOf(t2.getTime() / 1000 * 1000).multiply(ONE_BILLION ).add(BigInteger.valueOf(t2.getNanos()));
        diffTime   = firstTime.subtract(secondTime);
        System.out.println(firstTime);
        System.out.println(secondTime);
        System.out.println(diffTime);
    }
}