how to measure time in java code example

Example 1: java time code

final long startTime = System.currentTimeMillis();
for (int i = 0; i < length; i++) {
  // Do something
}
final long endTime = System.currentTimeMillis();

System.out.println("Total execution time: " + (endTime - startTime));

Example 2: calculate time java

System.out.println(LocalTime.now());