Calling a java application from another

Hello,
i have noticed a strange behaviour of my java app when i open it from another java app. When i run the core application with a bat file using jre1.6 everything works fine. Now what i want to do is create an application that checks the existance of jre 1.6, downloads it if it does not exist and run real application with the new jre. The second small app runs with a small jre 1.4.2. In reality it seem to work fine, it downloads the jre1.6 folder and exits normally. However when the real application is launched it behaves strangely without throwing any exceptions. And this behaviour seems to be random. for example, a jpanel may not show any components, or the whole jframe may close suddenly. Does anyone have any idea what is going on? Is there a chance that some classes of the first jre remain in memory and conflict when the second application is launched?

Just a wild guess: maybe you're invoking the java 1.6 binaries, but JAVA_HOME or something is pointing to java 1.4 libraries (or vice-versa), and you've found some weird interaction issue.

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Calling Java Application from another

How can i call a Java Application from another java App.
eg., If my Java application is called MyApp and i would like call another java application from within it.
One way could be by using "System". I would like to know if there is any other method and is portable.
Thanks in advance.

hi,
it works and not!
if you start an other class with a command like this the 2nd prog/class terminates too if you terminate the caller-class!
dear
oliver scorp

How to call a Java class from another java class ??

Hi ..... can somebody plz tell me
How to call a Java Class from another Java Class assuming both in the same Package??
I want to call the entire Java Class (not any specific method only........I want all the functionalities of that class)
Please provide me some slotuions!!
Waiting for some fast replies!!
Regards
Smita Mohanty

Hi Smita,
you just need to create an object of that class,thats it. Then you will be able to execute each and every method.
e.g.
you have developed A.java and B.java, both are in same package.
in implementaion of B.java
class B
            A obj = new A();
             //to access A's methods
             A.method();
            // to access A's variable
            //either
           A.variable= value.
           //or
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Call a Java Application from MicroFocus COBOL (in UNIX environment)

Hello,
Could you please let me know, how to call a Java application from a MicroFocus COBOL application. If anyone has any code samples, that would be of great help.
Thanks in advance,
Tijo.

You generally can't cause a program to be executed on a different >server. Basic security, you know. Besides this idea of having the Java >application run on a different server wasn't mentioned in your original >post. That leads me to believe we don't have the whole story.So I think you need to step back and find out what are the requirements. For example: Does your program need to start this Java application running, or is it already running and your program needs to connect to it somehow?
My program has to start a Java class file, meaning that the Micro Focus COBOL module will call the Java class file. Will it be running on the same machine as your program, or on some other machine?
For both cases, I would like to know the answer.a) Running on the same machine as my program is running.
b) Running on the different machine.
And then there are the questions about whether your program needs to have a conversation with the Java application, or whether it just needs to start it and that's all.
COBOL program has to call a Java class by passing some parameters and Java class in turn process it and return some value back.. Kind of Request and Response model.Plenty of questions to be asked. Go and find out what they are.
Sorry ... if I am not clear on my questions. Anyhow, thank you very much for providing the information.

Calling a Java Application from MicroFocus COBOL.... (in UNIX environment)

Hello,
Could you please let me know, how to call a Java application from a MicroFocus COBOL application. If anyone has any code samples, that would be of great help.
Thanks in advance,
Tijo.

Annoyingly crossposted.
http://forum.java.sun.com/thread.jspa?threadID=730657

Calling A Webdynpro Application From Another Webdynpro Application

Hi,
i want to call a webdynpro application from another webdynpro application with sending parameters.
i used this method,
CALL METHOD cl_wd_utilities=>construct_wd_url
    EXPORTING
      application_name = lv_webapp
    IMPORTING
      out_absolute_url = lv_url.
CONCATENATE lv_url '?param1=' lv_param INTO lv_url.
data lo_window_manager type ref to if_wd_window_manager.
data lo_api_component type ref to if_wd_component.
data lo_window         type ref to if_wd_window.
lo_api_component = wd_comp_controller->wd_get_api( ).
lo_window_manager = lo_api_component->get_window_manager( ).
lo_window         = lo_window_manager->CREATE_EXTERNAL_WINDOW(
    URL = LV_URL
lo_window->open( ).
but this method shows the parameters on the address bar.
is there a method to send the parameters to another webdynpro application without show the parameters on the address bar?
Can somebody help me pls?
Thanks.

I've used a server cookie before. This was built for BSP, but it is really usable anywhere. It just writes the data temporary into the database. This way you can just pass one meaningless URL parameter - like a GUID and use this key to read the data (the server cookie) upon initialization of the new application. I generally serialize all the data that I want into one server cookie by serializing a class. I can then restore whatever attributes of the class that I want on the receiving side.
http://help.sap.com/saphelp_nw70ehp1/helpdata/en/bd/4cd23a09313b37e10000000a11405a/frameset.htm

Calling a java application from j2ee web application

Hi,
I have a j2ee application in which i am making a call to a jar file which is a java application.
Runtime a4 = Runtime.getRuntime();
Runtime a = Runtime.getRuntime();
String cmd[] = new String[14];
cmd[0] = "cmd";
cmd[1] = "/c";
cmd[2] = "start";
cmd[3] = "javaw";
cmd[4] = "-jar";
cmd[5] = CATALINA_HOME+"\\webapps\\AveksaTesting\\AveksaTestingJava\\dist\\AveksaTestingJava.jar";
cmd[6] = SERVER_TESTS;
cmd[7] = COLLECTOR_TESTS;
cmd[8] = SYSTEM_TESTS;
cmd[9] = CREATE_ORACLE;
cmd[10] = DB_NAME;
cmd[11] = DB_DUMP;
cmd[12] = email;
cmd[13] = isMIGRATE;
try{
java.lang.Process p = a.exec(cmd);
Now in the called java application, i am first shutting down the tomcat server by calling shutdown.bat script and then starting it using startup.bat. But the problem i am facing is when i restart the server from java application, it says address already in use(i.e. port 8445 on which tomcat is runninng).
Id i just call the java application and do the same operation it works fine. I guess when i am calling java from j2ee application, j2ee still has some threads holding java and not shutting down tomcat properly.
Can anyone suggest me what can be done in this case. I have to call a java application from j2ee and restart the tomcat server many times.
Thanks in advance
-Vikram

Annoyingly crossposted.
http://forum.java.sun.com/thread.jspa?threadID=730657

Invoke one java application from another?

Hello,
Can anyone tell me how to Invoke one java application from another?
Suppose I have a small java application say, Hello.java which has its own main() method and
I also have another java application, say World.java which has its own main() method too.
What I want to do is invoke or startup World.java from Hello.java.
If possible kindly give code examples?

main is just a normal method so Hello can invoke the main method of World just as it would invoke any other method.
Kaj

Calling Webdynpro Java Application from Webdynpro ABAP Application.

Hi,
We have developed one Application using Webdynpro Java and I m in need to call the Webdynpro Java application from Webdynpro ABAP.
Require Suggestions to acheive this.
Thanks In advance.
Reg,
Ajay.

Dear Ajay,
Assuming that both your applications WDA & WDJ are in the portal & you don't have to pass any parameters to the WDJ application.
Write the following code on the action where you would call the WDJ application.
DATA:
        lr_compcontroller TYPE REF TO ig_componentcontroller,
        l_component TYPE REF TO if_wd_component ,
        lr_port_manager TYPE REF TO if_wd_portal_integration ,
        wa_navigation TYPE navigation.
lr_compcontroller =   wd_this->get_componentcontroller_ctr( ).
l_component = lr_compcontroller->wd_get_api( ).
lr_port_manager = l_component->get_portal_manager( ) .
* The value inserted into the navigation-target field can be found in the Portal
* content administration tab of your portal. It is the ID or PCD Location field
wa_navigation-target = pcd. " Please provide the PCD Location of the WDJ Application here.
wa_navigation-mode   = '0'. "0 = INTERNAL(same page) and 1 = EXTERNAL(new page).
CALL METHOD lr_port_manager->navigate_absolute
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      navigation_target = wa_navigation-target
      navigation_mode   = wa_navigation-mode.
You can get the PCD from the Page properties of the WDJ application page in the Portal.
Hope it helps!
Warm regards,
Upendra Agrawal

Calling a BSP application from another

Hello,
    I have not a lot experince in bsp's programming.
    I am trying to call a bsp applicattion from another one. Do you know how can I do it?.
    Thanks in advance. Javier.

hi Javier,
For questions on BSP programming,you should post your questions on the bSP forum.
For your question,it depends on how you want to call your BSP application.
Do you want to navigate from one BSP page to other or you want some link which leads to the other BSP application.?
You can find sufficient help on the help.sap.com
<a href="http://help.sap.com/saphelp_nw04/helpdata/en/e9/bb153aab4a0c0ee10000000a114084/frameset.htm">http://help.sap.com/saphelp_nw04/helpdata/en/e9/bb153aab4a0c0ee10000000a114084/frameset.htm</a>
For more details, you can search SDN itself.
IF you have more queries,your'e welcome.
Regards,
Siddhartha

Help with calling a java application from inside another one

Hello!
I am having this problem which is getting on my nerves and dont know how to solve..
I want to call from my java application, another java application. So i use the exec command. Then i want to read the output of this execution from my own application, (the "parent" process).
But it doesn work properly. Something seems to happen and i dont get the whole output.
The java program i want to call is created for running an application created with Matlab java builder.
This program works when called from cmd, but seems not to work when called from inside a java application.
The code of my java application is:
Runtime rt = Runtime.getRuntime();
Process child;
// The java class getmagic is a special kind of java file that uses classes that work in matlab. It uses a component (.jar) file that is created from matlab java builder. thats why it wants the -classpath and the rest options.
//I hope you wont get messed up in here.
String[] callAndArgs = {"java","-classpath",".;C:\\Program Files\\MATLAB\\R2006b\\toolbox\\javabuilder\\jar\\javabuilder.jar;..\\MagicDemoComp\\magicsquare\\distrib\\magicsquare.jar -Djava.library.path=C:\\Program Files\\MATLAB\\R2006b\\bin\\win32;","getmagic","4"};
try{
child = rt.exec(callAndArgs);
InputStream is = child.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null)
System.out.println(line);
is.close();
System.out.println(child.waitFor());
System.out.println("Finished");
}catch(IOException e) {
System.err.println("IOException starting process!");
}catch(InterruptedException e) {
System.err.println("InterruptedException starting process!");
The java program (getmagic) thats uses matlab gives the following output (after some time) when called in cmd with argument 4
Magic square of order 4
16 2 3 13
5 11 10 8
9 7 6 12
4 14 15 1
My program shown above only prints:
Magic square of order 4
1
Finished.
Do i do something wrong? How can i get the rest of the output???
Thank you very much in advance,
Stacey
PS: I am sorry for the length of my post.

Hello CaptainMorgan08, thanx for the instant reply.
I tried, but no, i cant.
Because i cannot include this java aplication that uses matlab into my application, cause 1) it needs special arguments in the compiler and during execution so it can be run and 2) it uses classes that java doesnt have. only the java-like matlab code.
For example it uses:
import com.mathworks.toolbox.javabuilder.*;
import magicsquare.*; //the component which is made from matlab java builder.
So i cannot compile it with my application!
If you know of a way, please let me know!
I know i might be missing something.. something that is obvious to you.. but i ve been working days=nights hardly no sleep..so you can excuse me if i say something foolish..
Message was edited by:
Stacey_Gr

Calling a java application from within another class

I have written a working java application that accepts command line parameters through public static void main(String[] args) {} method.
I'm using webMethods and I need to call myapplication from within a java class created in webMethods.
I know I have to extend my application class within the webMethods class but I do not understand how to pass the parameters.
What would the syntax look like?
Thanks in advance!

why do you want to call the second class by its main method ??
Why not have another static method with a meaningfull name and well defined parameters ?
main is used by the jvm as an entry point in your app. it is not really meant for two java applications to communicate with each other but main and the code is not really readable.
Have a look at his sample
double myBalance = Account.getBalance(myAccountId);
here Account is a class with a static method getBalance which return the balance of the account id you passed.
and now see this one, here Account has a main method which is implemented to call getBalance.
String[] args = new String[1];
args[0] = myAccountId;
Account.main(args);
the problem with the code above is
main doesn't return anything so calling it does do much good. two the code is highly unreadable because no one know what does the main do... unlike the sample before this one where the function name getBalance clearly told what is the function doing without any additional comments.
hope this helps.... let me know if you need any additional help.
regards,
Abhishek.

Launching a java application from another java application

Hi,
I'm facing an interesting challenge :-)
Inside a Java application, I want to start another java application.
Possible solutions in my list :
1. Using jakarta commons launcher.
2. Runtime.exec (make the code platform dependent).
3. Starting the main method of the other app by create a new Thread inside the current app
4. I know people did this by calling an ant target from the java application but I don't have
any sample code, I appreciate any sample code for it.
Thanks,
Ali Salehi

That is an iteresting challenge :)Don't be mean; he's polite, done some investigation and taken the trouble to be clear. The question, presumably, is "has anyone got a different solution or a preference as to which of these is the best?"
In which case, my advice would be to say that invoking main in a separate thread is fundamentally different from Runtime.exec() because the former would run in the same JVM. Is this what you want? If one app has the other on its classpath then do they need to be separate apps? Could they be modules of a single app?

How to call a C function calling a Java Method from another C function ?

Hi everyone,
I'm just starting to learn JNI and my problem is that I don't know if it is possible to call a C function calling a Java Method (or doing anything else with JNI) from another C function.
In fact, after receiving datas in a socket made by a C function, I would like to create a class instance (and I don't know how to do it too ; ) ) and init this instance with the strings I received in the socket.
Is all that possible ?
Thank you very much for your help !

Hard to understand the question, but by most interpretations the answer is going to be yes.
You do of course understand that JNI is the "API" that sits between Java and C and that every call between the two must go through that. You can't call it directly.

Calling one java program from another

Hello,
How can I start another java program from one? Lets
say I want Second.java to start by calling it from
First.java. How do I do it? The two programs are given
below. Any help is appreciated.
Thanks,
Amanda
First.java
import java.io.*;
import java.lang.reflect.*;
public class First
     public static void main(String[] args)
          Process theProcess=null;
          System.out.println("Hello World from First.java!");
          String second=new String("Second.java");
          //System.load(second);
          //Runtime.getRuntime().load(second);
          try
               theProcess=Runtime.getRuntime().exec( "Second.java"
               System.out.println("after exec");
          catch (IOException ioe)
               System.out.println(">>IOException thrown in
First.java while calling
Second.java."+ioe.getMessage());
Second.java
public class Second
     public static void main(String[] args)
          System.out.println("Hello World from Second.java!");
}

Thanks, warnerja
What if Second.java is on a remote machine i.e.
First.java and second.java are on different machines?
Will I have to use RMI?Well, you'd have to do some kind of remote invocation. Depends on what kinds of apps house the classes. There are all kinds of ways - web services, servlets, RMI, (maybe others...)
That's a totally different question than what you originally posted, and would have been very relevant to say so in the first place.

Calling a java application from another

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