JMX Metrics Quick Access with Java

import javax.management.*;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
import java.util.Set;

/**
 * This class demonstrates how to list JMX namespaces and MBeans on a remote JMX server.
 */
public class ListJMXNamespaces {
    /**
     * The main entry point of the program.
     *
     * @param args Command-line arguments (not used in this example).
     */
    public static void main(String[] args) {
        // Press Opt+Enter with your caret at the highlighted text to see how
        // IntelliJ IDEA suggests fixing it.
        System.out.printf("Hello and welcome!");

        // Define the JMX server URL
        String jmxUrl = "service:jmx:rmi:///jndi/rmi://localhost:9010/jmxrmi";

        try {
            // Create a JMX connector to connect to the remote JMX server
            JMXServiceURL serviceURL = new JMXServiceURL(jmxUrl);
            JMXConnector connector = JMXConnectorFactory.connect(serviceURL);

            // Connect to the MBean server
            MBeanServerConnection mbeanServerConnection = connector.getMBeanServerConnection();

            // List all MBeans and their object names
            System.out.println("Listing all MBeans and their namespaces:");
            Set<ObjectName> mbeanNames = mbeanServerConnection.queryNames(null, null);
            for (ObjectName mbeanName : mbeanNames) {
                //System.out.println("MBean: " + mbeanName);
                String namespace = mbeanName.getDomain(); // Extract the namespace
                //System.out.println("Namespace: " + namespace);
                System.out.println(namespace + " " + mbeanName);
            }

            // Close the JMX connector
            connector.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import javax.management.*;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;

/**
 * This class represents a JMX client that connects to a remote JMX server to retrieve and print
 * attribute values of a specified MBean (Managed Bean) object at regular intervals.
 */
public class JMXClient {

    /**
     * The main entry point of the JMX client application.
     *
     * @param args Command-line arguments. Expects two arguments: <ObjectName> and <DelayInMillis>.
     *             <ObjectName> specifies the target MBean's ObjectName, and <DelayInMillis> is
     *             the delay between metric checks in milliseconds.
     *             Example: java JMXClient metrics:name=com.hivemq.jvm.memory.heap.used 2000
     * @throws Exception If there are errors in the JMX connection or attribute retrieval.
     */
    public static void main(String[] args) throws Exception {
        if (args.length != 2) {
            System.err.println("Usage: java JMXClient <ObjectName> <DelayInMillis>");
            System.err.println("Example: java JMXClient metrics:name=com.hivemq.jvm.memory.heap.used 2000");
            System.exit(1);
        }

        // Parse command-line arguments
        String objectNameStr = args[0];
        long delayInMillis = Long.parseLong(args[1]);

        // Define the JMX service URL for connecting to the remote JMX server
        String jmxUrl = "service:jmx:rmi:///jndi/rmi://localhost:9010/jmxrmi";
        JMXServiceURL serviceURL = new JMXServiceURL(jmxUrl);
        JMXConnector connector = JMXConnectorFactory.connect(serviceURL);
        MBeanServerConnection connection = connector.getMBeanServerConnection();

        // Define the ObjectName based on the command-line argument
        ObjectName mbeanName = new ObjectName(objectNameStr);

        // Run indefinitely with the specified delay between checks
        while (true) {
            // Fetch and print the metric value
            Object metricValue = connection.getAttribute(mbeanName, "Value");
            System.out.println(objectNameStr + " " + metricValue);

            // Sleep for the specified delay before the next check
            Thread.sleep(delayInMillis);
        }
    }
}