Question

How to measure execution time in Java

Answer 1

import java.util.concurrent.TimeUnit;

public class MyClass {
    public static void main(String args[]) {
        try {
            long startTime = System.nanoTime();
    
            TimeUnit.SECONDS.sleep(2);
     
            long endTime = System.nanoTime();
     
            long timeElapsed = endTime - startTime;
     
            System.out.println("Execution time in nanoseconds: " + timeElapsed);
            System.out.println("Execution time in milliseconds: " + timeElapsed / 1000000);
        } catch (InterruptedException ie) {
            System.out.println("Error: " + ie);
        }
    }
}



/*
run:

Execution time in nanoseconds: 2000395671
Execution time in milliseconds: 2000

*/

 

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Answer 2

import java.util.concurrent.TimeUnit;

public class MyClass {
    public static void main(String args[]) {
        try {
            long startTime = System.currentTimeMillis();
 
            TimeUnit.SECONDS.sleep(2);
 
            long endTime = System.currentTimeMillis();
 
            long timeElapsed = endTime - startTime;
     
            System.out.println("Execution time in milliseconds: " + timeElapsed);
        } catch (InterruptedException ie) {
            System.out.println("Error: " + ie);
        }
    }
}



/*
run:

Execution time in milliseconds: 2000

*/

 

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Answer 3

import java.time.Instant;
import java.util.concurrent.TimeUnit;

public class MyClass {
    public static void main(String args[]) {
        try {
            long startTime = Instant.now().toEpochMilli();
 
            TimeUnit.SECONDS.sleep(2);
 
            long endTime = Instant.now().toEpochMilli();
 
            long timeElapsed = endTime - startTime;
 
            System.out.println("Execution time in milliseconds: " + timeElapsed);
        } catch (InterruptedException ie) {
            System.out.println("Error: " + ie);
        }
    }
}



/*
run:

Execution time in milliseconds: 2000

*/

 

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