Java Baseline Testing

Deploy a Java application with a Tomcat-like operation

Apache Tomcat is a widely used Java web application server. Technically, it is a Servlet container, responsible for executing Java servlets and supporting technologies such as:

• JSP (JavaServer Pages): Java-based templates for dynamic web content
• RESTful APIs: lightweight endpoints for modern microservices

In production, frameworks like Tomcat introduce additional complexity (such as request parsing, thread management, and I/O handling). Before layering those components, it’s useful to measure how efficiently raw Java executes simple request/response logic on Azure Cobalt 100 Arm-based instances.

In this section, you will run a minimal Tomcat-like simulation. It won’t launch a real server, but instead it will do the following:

• Construct a basic HTTP response string in memory
• Measure the time taken to build that response, acting as a microbenchmark
• Provide a baseline for raw string and I/O handling performance in Java

Using a file editor of your choice, create a file named HttpSingleRequestTest.java, and add the content below to it:

    

        
        
public class HttpSingleRequestTest {
    public static void main(String[] args) {
        long startTime = System.nanoTime();
        String response = generateHttpResponse("Tomcat baseline test on Arm64");
        long endTime = System.nanoTime();
        double durationInMicros = (endTime - startTime) / 1_000.0;
        System.out.println("Response Generated:\n" + response);
        System.out.printf("Response generation took %.2f microseconds.%n", durationInMicros);
    }
    private static String generateHttpResponse(String body) {
        return "HTTP/1.1 200 OK\r\n" +
               "Content-Type: text/plain\r\n" +
               "Content-Length: " + body.length() + "\r\n\r\n" +
               body;
    }
}

    

Compile and run the Java program

Compile the program and run it with modest heap sizes and the G1 garbage collector:

    

        
        
javac HttpSingleRequestTest.java
java -Xms128m -Xmx256m -XX:+UseG1GC HttpSingleRequestTest

    

JVM flags explained

• -Xms128m - sets the initial heap size to 128 MB
• -Xmx256m - sets the maximum heap size to 256 MB
• -XX:+UseG1GC - enables the G1 garbage collector designed for low pause times

Sample output

If the program runs successfully, you should see output similar to the following:

    

        
        java -Xms128m -Xmx256m -XX:+UseG1GC HttpSingleRequestTest
Response Generated:
HTTP/1.1 200 OK
Content-Type: text/plain
Content-Length: 29

Tomcat baseline test on Arm64
Response generation took 12901.53 microseconds.

        
    

Output breakdown

• Generated response: the program prints a fake HTTP 200 OK response with headers and a custom body string
• Timing result: the program prints how long it took (in microseconds) to build that response
• Variability: results change with CPU load, JVM warm‑up, and environment; run several times and use the median

Why this baseline matters

• Provides a Tomcat‑like request path without container overhead
• Enables x86_64 vs Arm64 comparisons on identical code and flags
• Informs GC and flag choices before testing full frameworks like Tomcat, Jetty, or Netty