You already know about method calls. What if the object that you want to invoke the method on is on a different computer? You use RMI to send the call from one computer (client) to the other (server). The client will wait (or “block”) until the result comes back from the server. This is called … Read more
We use something like the following to programatically connect to our JMX servers. You should run your server with something like the following arguments: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=1234 -Dcom.sun.management.jmxremote.ssl=false To bind to a particular address you’ll need to add the following VM arguments: -Djava.rmi.server.hostname=A.B.C.D Then you can connect to your server using JMX client code like … Read more
The web services do allow a loosely coupled architecture. With RMI, you have to make sure that the class definitions stay in sync in all application instances, which means that you always have to deploy all of them at the same time even if only one of them is changed (not necessarily, but it is … Read more
All of the methods on a RMI Remote interface must declare RemoteException in their throws clause, e.g.: public String getId() throws RemoteException; It’s not clear why the exception names getId() specifically, it’s probably just the first method it checked. Also, the getLeafNodes() and getNeighborhoodList() methods should have return types that specify Node, not NodeImpl, otherwise … Read more
Essentially the RMI registry is a place for the server to register services it offers and a place for clients to query for those services. See Introduction to Java RMI. Excerpt: Figure 1 shows the connections made by the client when using RMI. Firstly, the client must contact an RMI registry, and request the name … Read more
This is item A.1 in the RMI FAQ. You need to either fix your /etc/hosts file or set the java.rmi.server.hostname property at the server.
EJBs are built on top of RMI. Both imply Java clients and beans. If your clients need to be written in something else (e.g., .NET, PHP, etc.) go with web services or something else that speaks a platform-agnostic wire protocol, like HTTP or XML over HTTP or SOAP. If you choose RMI, you don’t need … Read more
Well, based on the definition of: A deadlock is a situation wherein two or more competing actions are each waiting for the other to finish. I would say that the answer is no – sure a thread can sit there waiting indefinitely for something, however unless two competing actions are waiting for each other it … Read more
Contrary to common belief JMX/RMI doesn’t need to open all these ports. You can actually force them to be same which will mean that at the end of the day you’ll only need to punch one hole in the firewall (if firewall is your concern). Try setting System Properties: com.sun.management.jmxremote.port com.sun.management.jmxremote.rmi.port to the same value!! … Read more
RPC is C based, and as such it has structured programming semantics, on the other side, RMI is a Java based technology and it’s object oriented. With RPC you can just call remote functions exported into a server, in RMI you can have references to remote objects and invoke their methods, and also pass and … Read more