Is there any way where I can find out which Java options are being used by a Java application inside JVM (e.g. the ones passed through the command line)?
I want to find it on the fly when the application is running, but from outside outside the application.
Map<String, String> env = System.getenv();
for (String envName : env.keySet()) {
System.out.format("%s=%s%n", envName, env.get(envName));
}
You can use JMX:
final JMXConnector connector = JMXConnectorFactory.connect(new JMXServiceURL(connectorAddress));
final MBeanServerConnection mBeanServerConnection = connector.getMBeanServerConnection();
final ObjectName commandLine = new ObjectName("java.lang:type=Runtime");
final List<Attribute> arguments = mBeanServerConnection.getAttributes(commandLine, new String[] {"InputArguments"}).asList();
String[] inputArguments = (String[]) arguments.get(0).getValue();
System.out.println(Arrays.asList(inputArguments));
connector.close();
To get the JMX connection, you might find my answer to " JMX client accessible locally only " helpful.
Use JMX. It allows to get options, properties, etc. from inside as well as outside of application.
I believe that Java does not support the "INTERCEPTING" of method arguments, method args are not logged or intercepted in the JVM .
However, you can easily print out the args sent to a running class using the System.env example in the other answer on this thread .
HOWEVER, if you have control over the actual applications source code, you can follow the directions here : How do I intercept a method invocation with standard java features (no AspectJ etc)?
This will allow you to log and intercept the args being sent to the main method.
