calculating execution time in java code example

Example 1: java execution time

long start = System.currentTimeMillis();
class.method();
long time = System.currentTimeMillis() - start;

Example 2: java measure execution time

Instant start = Instant.now();
Thread.sleep(63553);
Instant end = Instant.now();
System.out.println(Duration.between(start, end)); // prints PT1M3.553S