Getting a list of active sessions in Tomcat using Java

Question

I am developing a project in Java in which I want the count of all active sessions in Tomcat. Based on that I want to see how much of those users are active and actually usi

Answer 1

Here is the Java 7 style JMX code snippet (what basZero asked for and exactly does the job what Janning described):

JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:9999/jmxrmi");
try(JMXConnector jmxc = JMXConnectorFactory.connect(url)) {
  MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();
  ObjectName mbeanName = new ObjectName("Catalina:type=Manager,context=/,host=localhost");
  Object value = mbsc.getAttribute(mbeanName, "activeSessions");
}

Of course you need to replace root context (/) in ObjectName with your app context string if it is not deployed in the root context. See my detailed explanation on the Catalina JMX issue here: Accessing built-in MBeans in Tomcat programatically