Sample code snippet showing measurement of actions within a Java servlet and returning the information back to the browser

perf_measurement_servlet.java

import java.io.PrintWriter;
import java.text.DecimalFormat;
import javax.servlet.http.HttpServletResponse;

final long lngStart;
final long lngEnd;
final double dblElapsedTime;

// Get timestamp
lngStart = System.currentTimeMillis();

// ...do things that you want to measure

// Get timestamp
lngEnd = System.currentTimeMillis();

dblElapsedTime = ((double)(lngEnd-lngStart))/1000;
		
// Round off to a single decimal
DecimalFormat df = new DecimalFormat("#.#");

PrintWriter out = response.getWriter();

// Set some standard HTTP Response Headers
response.setContentType("text/html");
response.setCharacterEncoding("UTF-8");
response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");

out.println("<p>Took [<font color=blue>" + df.format(dblElapsedTime) + "</font>] seconds </p>");
out.flush();
out.close();