JAVA

java calculate time difference

You can use calendar
calendarMilis = c.timeInMillis.toInt() - System.currentTimeMillis().toInt()

java time difference

import java.time.Duration;
import java.time.Instant;
...
Instant start = Instant.now();
//your code
Instant end = Instant.now();
Duration timeElapsed = Duration.between(start, end);
System.out.println("Time taken: "+ timeElapsed.toMillis() +" milliseconds");