Accesing a class from a different PC on Internet

Hi all. I have the following problem:
I have a Java programa that access to serial port to send data to a device. It works good.
Also I have Jakarta Tomcat installed, and a servlet that instantiate the previous java program that access to serial port.
If this PC is connected directly to Internet, there are no problems to people from Internet can send data to serial port.
But I would like to put the device connected to another computer not connected directly to Internet.
I know Jakarta Topmcat should be on the PC connected directly to Internet, but...are there any possibility that my servlet call my Java serial port programme on a different computer ? E.g: using a special nomination before the class name...Also someone told I should use Java RMI...Dont know if its very difficult to use...
Would appreciate some advice or example code...
Thanks...
John

RMI seems to be a perfect solution to your problem. It isn't difficult to use, but will involve a little learning. It's a cool technology though, and should be fun to mess around with.
To learn it go to http://java.sun.com/docs/books/tutorial/rmi/index.html
The example that they use is cool, it's where I learned it first.
Dave

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Invoke a method in one class from a different class

I am working on a much larger project, but to keep this simple, I wrote out a little test that would convey the over all theory of the program.
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Thanks

So, how do I invoke a method in a class from a different class?Demo:
public class Main {
    public static void main(String [] args) {
     Test1 t1 = new Test1();
     Test2 t2 = new Test2();
     int i = t1.method1();
     String s = t2.method2(i);
     System.out.println(s);
class Test1 {
    public int method1() {
     return 10;
class Test2 {
    public String method2(int i) {
     if (i == 10)
         return "ten";
     else
         return "nothing";
}Output is "ten".
Edited by: newark on May 28, 2008 10:55 AM

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Can not access the Instance Data of a Singleton class from MBean

I am working against the deadline and i am sweating now. From past few days i have been working on a problem and now its the time to shout out.
I have an application (let's call it "APP") and i have a "PerformanceStatistics" MBean written for APP. I also have a Singleton Data class (let's call it "SDATA") which provides some data for the MBean to access and calculate some application runtime stuff. Thus during the application startup and then in the application lifecysle, i will be adding data to the SDATA instance.So, this SDATA instance always has the data.
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I tried all sorts of DATA class being final and all methods being synchronized, static, ect.,, just to make sure. But no luck till now.
Another unfortunate thing is that, i some times get different "ServicePerformanceData " instances (i.e. when i print the ServicePerformanceData.getInstance() they are different at different times). Not sure whats happening. I am running this application in WebLogic server and using the JConsole.
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http://www.velocityreviews.com/forums/t135852-rmi-singletons-and-multiple-classloaders-in-weblogic.html
http://www.theserverside.com/discussions/thread.tss?thread_id=12194
http://www.jguru.com/faq/view.jsp?EID=1051835
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I am working against the deadline and i am sweating now. From past few days i have been working on a problem and now its the time to shout out.
I have an application (let's call it "APP") and i have a "PerformanceStatistics" MBean written for APP. I also have a Singleton Data class (let's call it "SDATA") which provides some data for the MBean to access and calculate some application runtime stuff. Thus during the application startup and then in the application lifecysle, i will be adding data to the SDATA instance.So, this SDATA instance always has the data.
Now, the problem is that i am not able to access any of the data or data structures from the PerformanceStatistics MBean. if i check the data structures when i am adding the data, all the structures contains data. But when i call this singleton instance from the MBean, am kind of having the empty data.
Can anyone explain or have hints on what's happening ? Any help will be appreciated.
I tried all sorts of DATA class being final and all methods being synchronized, static, ect.,, just to make sure. But no luck till now.
Another unfortunate thing is that, i some times get different "ServicePerformanceData " instances (i.e. when i print the ServicePerformanceData.getInstance() they are different at different times). Not sure whats happening. I am running this application in WebLogic server and using the JConsole.
Please see the detailed problem at @ http://stackoverflow.com/questions/1151117/can-not-access-the-instance-data-of-a-singleton-class-from-mbean
I see related problems but no real solutions. Appreciate if anyone can throw in ideas.
http://www.velocityreviews.com/forums/t135852-rmi-singletons-and-multiple-classloaders-in-weblogic.html
http://www.theserverside.com/discussions/thread.tss?thread_id=12194
http://www.jguru.com/faq/view.jsp?EID=1051835
Thanks,
Krishna

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I am having some problems accessing my custom classes from my JSP.
1) I've created a very simple class, SimpleCountingBean that just has accessors for an int. The class is in the package "SimpleCountingBean". I compiled this class locally on my laptop and uploaded the *.class file to my ISP.
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Trying to get some clearer view.. so don't mind..
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Post again if you have more questions!

Accesing a class from a different PC on Internet

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