Total method time in Java VisualVM

Question

In Java VisualVM, is there any way to display total method time, rather than \"self time\"? (The latter is not particularly useful, since it doesn\'t tell you anything about

Answer 1

JavaAssist is a class library to manipulate your Java Byte Code without touching the source. Let's take an example of measuring time taken to execute a method.

public class Subject {
    /**
     * Timetaken for start & end of the method
     * 
     * @throws InterruptedException
     */
    public void method2() throws InterruptedException {
        // Some business logic :)
        Thread.sleep(2000);
    }
}

To measure time taken for executing subject.method2(), you could enhance the Subject.methods() by adding code start and end of the method as shown.

public class JavaAssist {
    public static void main(String[] args) {
        timeTaken();
    }

    public static void timeTaken() {
        try {
            ClassPool p = ClassPool.getDefault();
            CtClass cc = p.get("Subject");
            CtMethod meth2 = cc.getDeclaredMethod("method2");
            meth2.insertBefore("System.out.println(\" Start : \"+new java.util.Date());");
            meth2.insertAfter("System.out.println(\" End : \"+new java.util.Date());");
            // cc.writeFile(".");
            Class c = cc.toClass();
            Subject s = (Subject) c.newInstance();
            s.method2();
            cc.detach();
        } catch (Exception e) {
            // suppressed
        }
    }
}

Output: Start : Wed May 26 17:24:18 EDT 2010 End : Wed May 26 17:24:20 EDT 2010

Reference http://www.csg.is.titech.ac.jp/~chiba/javassist/tutorial/tutorial.html#read

http://www.csg.is.titech.ac.jp/~chiba/javassist/html/

Origin Post from: http://www.senthilb.com/2010/05/javaassist-byte-code-enhancement.html