Various Ways to Measure Code Execution Time in Java

In this article, a senior architect shares multiple approaches to measure the execution time of Java code, starting with a brief introduction that mentions the common use of System.currentTimeMillis() for simple timing.

StopWatch

The first method utilizes Spring's StopWatch utility. Example code:

StopWatch stopWatch = new StopWatch();
stopWatch.start();
//doInsert(); // execute business logic
stopWatch.stop();
System.out.println(stopWatch.getTotalTimeMillis());

The output displays the total elapsed time in milliseconds.

System.nanoTime()

The second method uses System.nanoTime() for higher‑resolution timing. Example code:

long startTime = System.nanoTime();
doInsert(); // execute business logic
long endTime = System.nanoTime();
System.out.println(endTime - startTime);

This prints the elapsed nanoseconds between the two calls.

new Date()

The third method employs new Date() objects. Example code:

Date startDate = new Date();
//doInsert(); // execute business logic
Date endDate = new Date();
System.out.println(endDate.getTime() - startDate.getTime());

The difference of the two timestamps yields the duration in milliseconds.

System.currentTimeMillis()

The fourth method simply references System.currentTimeMillis() , which is similar to the new Date() approach and is omitted for brevity.

Additional information about the StopWatch API is listed, including methods such as start(String taskName) , stop() , isRunning() , getTotalTimeMillis() , getTotalTimeSeconds() , and others that provide detailed timing capabilities.

The article concludes with a reminder to explore the source code of StopWatch , which internally relies on System.nanoTime() , and encourages readers to discuss and share their thoughts.

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