Develop Reference

MBean nested object name in JMX

I've noticed that some MBeans have nested keys; how do I make the query to get that key?
The image below shows an example:
Normally, the MBean query is like this: "org.apache.cassandra.metrics:type=CQL,name=RegularStatementsExecuted"
How do I add the additional folder to that query? I've tried the following:
"org.apache.cassandra.metrics:type=Cache,CounterCache,name=Capacity"
"org.apache.cassandra.metrics:type=Cache.CounterCache,name=Capacity"
"org.apache.cassandra.metrics:type=Cache,type=CounterCache,name=Capacity"
Any ideas?
I looked over Java Management Extensions (JMX) Best Practices and it doesn't mention anything about nested keys.

I noticed that I could add scope to the property list when I looked at jconsole:
So, what I used was:
"org.apache.cassandra.metrics:type=Cache,scope=CounterCache,name=HitRate"
It's nice to know that it's not documented anywhere...

To get all session ids of tomcat using JConsole which can be found at :-
Catalina > Manager > localhost > /##07 ( > Operations > listSessionIds )
To get the MBean object name of /##07 just click on it on JConsole and it will show the name.(As shown below)
Java code to fetch all the session Ids:
JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:9999/jmxrmi");
JMXConnector jmxConn = JMXConnectorFactory.connect(url, null);
// Connecting to the MBeanServer
MBeanServerConnection mbsConn = jmxConn.getMBeanServerConnection();
Object sessionIds = mbsConn.invoke(new ObjectName("Catalina:type=Manager,host=localhost,context=/##07"), "listSessionIds", null, null);
System.out.println(sessionIds.toString());
//close jmx connection
jmxConn.close();

Standalone ActiveMQ client on GlassFish

Hello guys i have such issue i make all thing like tutorial says. So now i want to lookup my Topics and connection factories that i configured but it do not see them. i make something like :
try {
Properties propertiesAMQ = new Properties();
propertiesAMQ.load(new FileInputStream("AMQ.properties"));
logger.info("Property file loaded succesfully...");
propertiesAMQ.setProperty(Context.INITIAL_CONTEXT_FACTORY,
"org.apache.activemq.jndi.ActiveMQInitialContextFactory");
propertiesAMQ.setProperty(Context.PROVIDER_URL,
"tcp://localhost:61616");
Context ctx = new InitialContext(propertiesAMQ);
javax.jms.TopicConnectionFactory factory = (javax.jms.TopicConnectionFactory) ctx
.lookup("amqpool");
javax.jms.Topic mytopic = (javax.jms.Topic) ctx.lookup("amqmsg")
}
And recieve NameNotFoundException. If i use name of connection factory such as "ConnectionFactory" it will be ok but then it will not see my Topic What i did wrong? Have u other examples of this subject? I'm using glassfish 3.0.1 and AMQ 5.5.0

Probably you are missing the namespace, you can look the exact name in the glassfish console, but most probably it should be;
javax.jms.Topic mytopic = (javax.jms.Topic) ctx.lookup("java:amqmsg")

How do you create your Topic resource? I had a similar problem and the solution was to create the Admin Resource Object using Glassfish command-line tool 'asadmin'. Creating it using the Glassfish admin console did not work (causing NameNotFoundException).
I ended up creating my Queu resource with the following command: 'create-admin-object –restype javax.jms.Queue –raname activemq-rar-5.7.0 –property PhysicalName=queueName queueName'

Getting instance ip from weblogic cluster

I have a problem on how to get an instance URL within a cluster with weblogic.
Description:
We have 2 domains: X and Y.
In each domain I have 2 clusters: c01 and c02
In each cluster I have instances: s01,s02,s03,s04
In each instances I have our system which contains of several components, let’s call the components A,B,C and D. I want to make a REST call from A to D which are still in the same instance. How will we get the URL and port to this REST service programmatically?
The problem is that I am just getting the cluster URL when calling InetAddress or alike. I have also played around with MBean, but we are not sure it’s correct way to go since I wont have any user/pass to fill in for Enviroment object when creating the context.
We don’t want this as a build property since we don’t want to do builds for each different instance.
Env:
SpringIntegration
Weblogic 10.3.3
Jersey
Maven
Thanks

Solution:
Got it from an RuntimeServiceMBean:
service = new ObjectName(
"com.bea:Name=RuntimeService,Type=weblogic.management.mbeanservers.runtime.RuntimeServiceMBean");
InitialContext ctx = new InitialContext();
MBeanServer mBeanServer = (MBeanServer) ctx.lookup("java:comp/env/jmx/runtime");
ObjectName rt = (ObjectName) mBeanServer.getAttribute(service, "ServerRuntime");
listenAddress = (String) mBeanServer.getAttribute(rt, "ListenAddress");
server = listenAddress.substring(0, listenAddress.indexOf("/"));
port = (Integer)mBeanServer.getAttribute(rt, "ListenPort");

Determine that application is running under application server

Some code may be reused in various environments including Java EE Application server. Sometimes it is nice to know whether the code is running under application server and which application server is it.
I prefer to do it by checking some system property typical for the application server.
For example it may be
jboss.server.name for JBoss
catalina.base for Tomcat
Does somebody know appropriate property name for other servers?
Weblogic, Websphere, Oracle IAS, others?
It is very easy to check if you have the specific application server installed. Just add line
System.getProperties() to any JSP, Servlet, EJB and print the result.
I can do it myself but it will take a lot of time to install server and make it working.
I have read this discussion: How to determine type of Application Server an application is running on?
But I prefer to use system property. It is easier and absolutely portable solution. The code does not depend on any other API like Servlet, EJBContext or JMX.

JBoss AS sets a lot of diffrent system properties:
jboss.home.dir
jboss.server.name
You can check other properties using for example VisualVM or other tools.
I don't know other servers but I think you can find some kind of properties for each of them.

This is not a 'standard' way but what I did was to try to load a Class of the AppServer.
For WAS:
try{
Class cl = Thread.getContextClassLoader().loadClass("com.ibm.websphere.runtime.ServerName");
// found
}
// not Found
catch(Throwable)
{
}
// For Tomcat: "org.apache.catalina.xxx"
Etc.
Let me know what you think

//for Tomcat
try {
MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();
ObjectName name = new ObjectName("Catalina", "type", "Server");
StandardServer server = (StandardServer) mBeanServer.getAttribute(name,"managedResource");
if (server != null) {
//its a TOMCAT application server
}
} catch (Exception e) {
//its not a TOMCAT Application server
}
//for wildfly
try {
ObjectName http = new ObjectName("jboss.as:socket-binding-group=standard-sockets,socket- binding=http");
String jbossHttpAddress = (String) mBeanServer.getAttribute(http, "boundAddress");
int jbossHttpPort = (Integer) mBeanServer.getAttribute(http, "boundPort");
String url = jbossHttpAddress + ":" + jbossHttpPort;
if(jbossHttpAddress != null){
//its a JBOSS/WILDFLY Application server
}
} catch (Exception e) {
//its not a JBOSS/WILDFLY Application server
}

Tomcat: Change the Virtual hosts programmatically?

Tomcat offers a build in "Virtual Hosting" Support: An Engine/Web-Application can be configured to be responsible for a list of Domains. These Domains have to be put into the server.xml/context.xml files with a special xml directive.
=> Is there any possibility to change the Tomcat Configuration (in general) and especially the "Virtual Hosts" of a Web-Application/Engine programmatically?
For example if a new user signs up, I have to add his domain to the list of "accepted virtual hosts/domains". The only way I currently think of is changing the xml files via a script and then restart Tomcat.
Is there any way to add them add runtime via some Java-Methods programmatically?
Thank you very much!
Jan

Tomcat provides APIs to create new virtual host. To get access to the wrapper object needed for this, you need to implement a ContainerServlet. You can create virtual host like this,
Context context = (Context) wrapper.getParent();
Host currentHost = (Host) context.getParent();
Engine engine = (Engine) currentHost.getParent();
StandardHost host = new StandardHost();
host.setAppBase(appBase);
host.setName(domainName);
engine.addChild(host);
You need to make sure appBase directory exist and you have to find ways to persist the new host to the server.xml or you lose the host on restart.
However, this approach rarely works. If your users run their own apps, you really want run separate instances of Tomcat so you can sandbox the apps better. e.g. One app running out of memory doesn't kill all other apps.
If you provide the app, you can just use one host (defaultHost). You can get the domain name from Host header and do whatever domain-specific stuff in your code.

You shouldn't change the server environment programmatically and there are no reliable and standard ways to do this. Best is to do and keep it all on the webapp side. To start, a Filter is perfectly suitable for this. Store the names somewhere in a database table or a properties file which you cache in the application scope. Check the HttpServletRequest#getRequestURI() (or the getServerName() if it is a subdomain instead of pathinfo) and do the forwarding task accordingly.
Hope this helps.

Use JMX
ArrayList serverList = MBeanServerFactory.findMBeanServer(null);
MBeanServer server = (MBeanServer) serverList.get(0);
Object[] params = { "org.apache.catalina.core.StandardHost", hostName };
String[] signature = { "java.lang.String", "java.lang.String" };
server.invoke(new ObjectName("Catalina:type=Engine"), "addChild", params, signature);
If needed, retrieve the host object and work with it:
ObjectName host = new ObjectName("Catalina:type=Host,host=" + hostName);
server.setAttribute(host, new Attribute("autoDeploy", false));
server.invoke(host, "start", null, null);

I would suggest you set your application to be the default virtual host in server.xml so your single virtual host can respond to requests addressed to any host name. Tomcat ships with the localhost application set as the default virtual host. So you can see how to do this by simply inspecting the server.xml file of a vanilla tomcat installation. You can programatically determine the host name the user sent the request to using the ServletRequest.getServerName() method.
Tomcat used to ship with a web application called "host-manager". Note: this is different than the "manager" web application that still comes with Tomcat. Host manager allowed for changing configuration or adding new virtual hosts on the fly without restarting the server. You could interact with the host-manager over HTTP (programmatically if desired). However, it had the unfortunate flaw of not committing its changes to server.xml so they were all lost on a web server restart. For whatever reason, starting with version 6, Tomcat no longer ships with the host-manager application. So it doesn't appear to be supported anymore.

To sum up ZZ Coder answer which guided me a lot:
You have to create a servlet that implements ContainerServlet and override setWrapper method to get the org.apache.catalina.Wrapper object.
For doing that you have to have privileged="true" in your context.xml Context tag or it will throw an exception. Then you can use the Wrapper object and:
StandardContext context = (StandardContext) wrapper.getParent();
StandardHost currentHost = (StandardHost) context.getParent();
StandardEngine engine = (StandardEngine) currentHost.getParent();
StandardHost host = new StandardHost();
host.setAppBase(currentHost.getAppBase()); //in my case I created another instance of the same application
host.setDomain(currentHost.getDomain());
host.setAutoDeploy(false); // not restarting app whenever changes happen
host.setName("domain.com");
host.setThrowOnFailure(true);// tell it to throw an exception here if it fails to create the host
host.setDeployOnStartup(true);
host.setStartChildren(true);
host.setParent(engine);
// you can add multiple aliases
host.addAlias(alias);
StandardContext ctx = new StandardContext();
ctx.setDocBase(context.getDocBase()); //again I reused my same application setting
ctx.setPath("");
if(currentHost.getWorkDir() != null)
{//create a working directory based on your new host's name
ctx.setWorkDir(currentHost.getWorkDir().replace(currentHost.getName(), host.getName()));
}
ctx.setName(host.getDomain());
//some extra config that you can use
ctx.setUseHttpOnly(false);
ctx.setReloadable(false);
ctx.setXmlValidation(false);
ctx.setXmlNamespaceAware(false);
ctx.setCrossContext(false);
ctx.setParent(host);
// you have to have this or it will not work!!
ctx.addLifecycleListener(new ContextConfig());
//you can also create resources and add it to the context like so:
final ContextResource res = new ContextResource();
res.setName("name");
res.setAuth("Container");
res.setType("javax.sql.DataSource");
ctx.getNamingResources().addResource(res);
host.addChild(ctx);
engine.addChild(host);
You can add properties to your resource by calling res.setProperty("name", "value")
Some properties that you can use are:
initialSize,maxTotal,maxIdle,maxWaitMillis,removeAbandonedOnBorrow,removeAbandonedTimeout,validationQuery,timeBetweenEvictionRunsMillis,driverClassName,url,username,password.
Another exciting thing to is to get the host from the tomcat engine by calling engine.findChild(domain) and use stop(), start(), getStateName() and have your own Tomcat Admin panel!