Tutorials about javaagents [closed]

The second case talks about Java Instrumentation API – this link points to a Javadoc which is rather descriptive.

And here, is the full instruction and an example of how to create java instrumentation agent.

The main concept is to:

1. Implement a static premain (as an analogy to main) method, like this:

   import java.lang.instrument.Instrumentation;
   
   class Example {
       public static void premain(String args, Instrumentation inst) {
           ...
       }
   }
   

2. Create a manifest file (say, manifest.txt) marking this class for pre-main execution. Its contents are:

   Premain-Class: Example
   

3. Compile the class and package this class into a JAR archive:

   javac Example.java
   jar cmf manifest.txt yourAwesomeAgent.jar *.class
   

4. Execute your JVM with -javaagent parameter, like this:

   java -javaagent:yourAwesomeAgent.jar -jar yourApp.jar