Launching a Java Program from UNIX ( C/C++ )

How do I launch my Java program from c/c++? Do I need to wrap my java command line ( ie. java -classpath .... ) in a C shell ? Is there another way?

How do I launch my Java program from c/c++? Do I need
to wrap my java command line ( ie. java -classpath
.... ) in a C shell ? Is there another way?You can do it directly using Java Native Interface (JNI). Using this approach the Java program runs in the current process.
Sylvia.

Similar Messages

Calling a Java Program from another

Hi,
I am putting together a Java program which will launch other Java programs.
I was thinking of doing this by calling unix scripts from my java program by getting an instance of the Runtime object and then calling the exec method with the script name.
I am just wondering what is the best practice when doing this? i.e., dealing with timeout issues, and errors in the scripts etc.
I have read this article, which is quite good: http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html?page=1
Is there any code available on the web that deals with all of the basic error scenarios?
Is it good practice to use a java program to call another java program? Or is there a better way of doing this?
The main reason I am using java is because I am most familiar with it and I need to connect to a database as well and do some manipulation of results returned.
Any thoughts or suggestions would be much appreciated.
Message was edited by:
LondonJavaDev

Thanks Prometheuzz
Is the main difference between your suggestion and
using the Runtime.getRuntime().exec(cmd) way of doing
things is that in the former both eill run as the
same process (Thread) but in the second scenario the
.getRuntime().exec(cmd) will start a separate new
thread?
Many ThanksCorrect. But you can create a sort of wrapper class for A which implements Runnable and stuff it in it's own thread. If you're dealing with Java code only, I advise you to create threads yourself instead of letting your OS handle them.
Here's a demo:
class Foo {
    public static void main(String[] args) {
        (new Thread(new ARunner())).start();
        B.main(null);
class ARunner implements Runnable {
    public void run() {
        A.main(null);
class A {
    public static void main(String[] args) {
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) { /* ... */ }
        System.out.println("A");
class B {
    public static void main(String[] args) {
        System.out.println("B");
}Of course, you can create a wrapper for B as well.

Launching Web Start Program from an Applet?

Hi,
I need to launch web start program from an applet.
How can I do that?
I have tried opening a new web page pointing to the jnlp file from an applet. But, that does not seem to start the web start.
Thanks in advance
rg

I am new to this so may be my questions will appear stupid to a pro, but this is an erro I am getting at compile:
Can't make static reference to method java.lang.Process exec(java.lang.String) in class java.lang.Runtime.
Runtime.exec("test.exe");
What could be the problem?
^

Start a java program from an FMB then read and write some variables

Hello,
I am trying to see whether the following setup works:
item A, B, D and Button Z are on a Forms Canvas.
User clicks on Button Z. This will launch a java program (Myprog class).
Myprog main will read values in item A and B, run some calculation and then will return it back to our forms module and then will be displayed in item D.
I have read about PL/SQL wrapper but the way I am looking at my setup is that my Forms module will be just the GUI interface.
Any ideas ?

main thing: a JAVA class that will take some inputs and will output some results and messages.
Prob: I do not want to use swing or any other GUI builder to make a nice GUI for my JAVA class.
What I want: I know how to use Forms. As such, I just want to put together a quick interface (mymodule.fmb) that when executed will allow the user to click on a button to start the java process and then see the results and error messages.
Why I don't want to go through SWING: my main prob is to get the java class executed ( which is fine right now thru command line) by other users thru a GUI interface. I do not have time to go thru SWING.
From the paper I mentioned, I think the PJC is the way to go. Can you please confirm ?
Thanks.

Execute a java program from an another program

Like we can compile a code from wihin a java file by using the following :
Tool javac = ToolProvider.getSystemJavaCompiler();
Similarly,can we execute i.e. run a java program from within a java file i.e. running d java command from within the java file ??If yes then please tell me how??

suppose on the Unix box or from a Unix script ( korn, perl, bourne, bash) you can run the following java program
java ${JAVA_OPTS} -jar ${GMR_APPS_DIR}/risk.jar -I -c ${COB} -r ${BATCH} -o ${XML_DIR}
in java you can do the following :
Runtime rt = Runtime.getRuntime();
          try {
               Process process = rt.exec("java ${JAVA_OPTS} -jar ${GMR_APPS_DIR}/risk.jar -I -c ${COB} -r ${BATCH} -o ${XML_DIR}
// OR
               Process process = rt.exec("/export/apps/Tools/apache-tomcat-5.5.17/bin/startup.sh");
               // process.destroy(); if you want to kill the process
               process.waitFor();
               int RC = process.exitValue();
               System.out.println(returnOutput(process.getErrorStream()));
               System.out.println(returnOutput(process.getInputStream()));
          } catch (Exception ex) {
               ex.printStackTrace();
empty the output stream from the script
private String returnOutput(InputStream is) throws Exception {
               String s;
               StringBuffer strBuff = new StringBuffer();
               BufferedReader br = new BufferedReader(new InputStreamReader(is));
               while ((s = br.readLine()) != null) {
                    strBuff.append(s);
               return strBuff.toString();
          }You need to relace the ${} by the appropriate values.
Regards,
Alan Mehio
London, UK
Edited by: alan_mehio on Jan 16, 2008 4:21 PM

Java program in UNIX environment

Hi All,
Could you please help me with how to configure a java program in UNIX environment..
that is to schedule it to run every day from cron..
I need to know what are the basic things we require to achieve the above..
I guess it is:
A script
A config file containing db login details
oher than this I don?t know what is required plz help

You can execute any jar or class file with cron. If you are using a jar you might use something like java -jar /usr/bin/myapp.jar .
I use Linux, this is my area of expertise.
Here is an online guide "for complete newbies" on how to set up cron.
http://www.unixgeeks.org/security/newbie/unix/cron-1.html
Hope it helps.

Launch many java programs at runtime

Hi i got one question.
i have a list of java program ina file.
i read this file and get each program names.
i would like to launch all java programs at Runtime from my main Java application.
here is my code so far:
String fileName = expansion + ".txt";
          try
               File file = new File(fileName);
               FileReader     fileReader= new FileReader(file);
               BufferedReader bufferReader = new BufferedReader(fileReader);
               while((program=bufferReader.readLine())!= null)
                    Runtime launch=Runtime.getRuntime();
                    System.out.println("I launch "+ program);
                    launch.exec("cmd.exe /c start /c cd /bin");
                    launch.exec("java "+program);
this does not work. How can i handle this?
thank you
seb

while((program==bufferReader.readLine())
!= null) {Sorry, I meant
while((program==bufferReader.readLine())!= null) {{=^)

How to submit a cuncurrent program from UNIX?

How to submit a concurrent program from UNIX.Plz reply immediatly

Please see;
Oracle Metalink Document: How to Submit a Concurrent Request Using CONCSUB Syntax: Doc ID: Note:457519.1
https://metalink.oracle.com/metalink/plsql/f?p=130:14:5250231761732667752::::p14_database_id,p14_docid,p14_show_header,p14_show_help,p14_black_frame,p14_font:NOT,457519.1,1,1,0,helvetica
Adith

Error while calling java program from ABAP

Hi Experts,
We are trying for RFC inbound scenario.
We followed the below blog
/people/gregor.wolf3/blog/2004/08/26/setup-and-test-sap-java-connector-outbound-connection
We are working with SAP JCO 3.0.2
We are getting the error : 'STFC_CONNECTION' could not be found in the server repository.
After I run the Java server program if I execute the RFC destination directly from SM 59 it is showing successful messages.
If I stop the java program then this RFC is failing. Based on this we concluded that RFC to Java connection is working fine.
But as mentioned in blog if we call the RFC Destination from ABAP program it is giving the below error,
'STFC_CONNECTION' could not be found in the server repository.
If we test the RFC destination using RFC_TRUSTED_CHECK standard FM we are getting the below error.
'RFCPING' could not be found in the server repository.
We create the RFC destination of Type : TCP/IP as exactly mention in the blog.
Please help us in resolving this issue.
Thanks
Prince

Pabi,
Using the RFC connection,we can establish a link between Java and SAP.
Afterwards,hope we can call Java program from ABAP.
Below is the sample piece of code to establish RFC connection(link) between Java and SAP.
DATA: REQUTEXT LIKE SY-LISEL,
      RESPTEXT LIKE SY-LISEL,
      ECHOTEXT LIKE SY-LISEL.
DATA: RFCDEST like rfcdes-rfcdest VALUE 'NONE'.
DATA: RFC_MESS(128).
REQUTEXT = 'HELLO WORLD'.
RFCDEST = 'JCOSERVER01'. "corresponds to the destination name defined in the SM59
CALL FUNCTION 'STFC_CONNECTION'
   DESTINATION RFCDEST
   EXPORTING
     REQUTEXT = REQUTEXT
   IMPORTING
     RESPTEXT = RESPTEXT
     ECHOTEXT = ECHOTEXT
   EXCEPTIONS
     SYSTEM_FAILURE        = 1 MESSAGE RFC_MESS
     COMMUNICATION_FAILURE = 2 MESSAGE RFC_MESS.
IF SY-SUBRC NE 0.
    WRITE: / 'Call STFC_CONNECTION         SY-SUBRC = ', SY-SUBRC.
    WRITE: / RFC_MESS.
ENDIF.
Regards,
Sree

URGENT: How to run a Java program from a different directory?

Hi.
How do I run a Java program from a directory that the file is not located in? So lets say im in c:\Java. But the file is in c:\Java\abc\efg\.
What would be the command to run the Java file from c:\Java.
I can't remember it and I need it asap.
Cheers.

If the class you are trying to run is MyApp.class, try
c:\Java\>java -cp abc\efg MyAppThe actual classpath you specify will depend on whether or not MyApp.class is in a package (I've assumed it isn't) and whether or not any 3rd party jars are involbed (I've assumed not).
Edited by: pbrockway2 on Apr 1, 2008 6:42 PM
The command arguments read as "Run the MyApp class using as a classpath abc\efg relative to here (c:\Java)".

Not able to execute one Java program from another one via. exec()

Hi,
I am new to this forum, so I might be asking a very trivial quetion.
My program Ap1 is :
class Ap1
public static void main(String a[]) throws Exception
Runtime rt=Runtime.getRuntime();
Process p=null;
p=rt.exec("javac,Pr.java");
Runtime.getRuntime().exec("javac,Pr.java");
When I run the above program, I get below error at the line 7(bold one):
D:\batchwe>javac Ap1.java
D:\batchwe>java Ap1
Exception in thread "main" java.io.IOException: CreateProcess: javac,Pr.java err
or=2
at java.lang.ProcessImpl.create(Native Method)
at java.lang.ProcessImpl.<init>(ProcessImpl.java:81)
at java.lang.ProcessImpl.start(ProcessImpl.java:30)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:451)
at java.lang.Runtime.exec(Runtime.java:591)
at java.lang.Runtime.exec(Runtime.java:429)
at java.lang.Runtime.exec(Runtime.java:326)
at Ap1.main(Ap1.java:7)
Path is set as below(which seems correct):
D:\batchwe>path
PATH=C:\Program Files\Java\jdk1.5.0_05\bin
I am just wondering how to call one Java program from another one?!
Please help.
thanks
Rashmi

Hi diptaPB,
Thanks for your suggestion.
Here is how I tried it again, but not getting the desired output:
Class Pr looks like below -->
class Pr
public static void main(String a[])
System.out.println("hi from process");
When I run 'Pr' from command prompt, i get the desired output:
D:\batchwe>java Pr
hi from process
However, when I call 'Pr' from another program Ap2.java, it seems that it does not call 'Pr':
class Ap2
public static void main(String a[]) throws Exception
Runtime rt=Runtime.getRuntime();
Process p=null;
String[] cmd=new String[2];
cmd[0]="javac";
cmd[1]="Pr.java";
p=rt.exec("cmd");
D:\batchwe>javac Ap2.java
D:\batchwe>java Ap2
************* no output appears here***********************
Looking forward for your help.
regards
Rashmi

How to call java program from ABAP

Hi Experts,
My requirement is to call java programs from ABAP. For that i have set up SAP JCO connection by using this link http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/739. [original link is broken] [original link is broken] [original link is broken] Connection gets sucessfully. After this how to call java program from ABAP as per our requirement. Please help me out.
Also i tried this way also.. but while executing the DOS Command line appear & disappear in few seconds. So couldnt see the JAVA output. Please help me out to call java programs in ABAP..
DATA:command TYPE string VALUE 'D:Javajdk1.6.0_20 injavac',
parameter TYPE string VALUE 'D:java MyFirstProgram'.
CALL METHOD cl_gui_frontend_services=>execute
EXPORTING
application = command
parameter = parameter
OPERATION = 'OPEN'
EXCEPTIONS
cntl_error = 1
error_no_gui = 2
bad_parameter = 3
file_not_found = 4
path_not_found = 5
file_extension_unknown = 6
error_execute_failed = 7
OTHERS = 8.
Thanks.

This depends on the version of your Netweaver Java AS. If you are running 7.0, you will have to use the Jco framework. The Jco framework is deprecated since 7.1 though. If you want to build a RFC server in 7.1 or higher, it is adviced that you set it up through JRA.
Implement an RFC server in 7.0:
http://help.sap.com/saphelp_nw04/helpdata/en/6a/82343ecc7f892ee10000000a114084/frameset.htm
Implement an RFC server in 7.1 or higher:
http://help.sap.com/saphelp_nwce72/helpdata/en/43/fd063b1f497063e10000000a1553f6/frameset.htm

Calling Java program from ABAP

Hi All,
my ABAP program downloads one file to one folder. Then one Java program is running to Encrypt the file.
Now , they want to call the JAVA program in ABAP, so that they can encrypt the file before downloading.
Is it possible to call a Java program from ABAP ? If Yes, please give me the detailed procedure.
Thanks
pabi

Pabi,
Using the RFC connection,we can establish a link between Java and SAP.
Afterwards,hope we can call Java program from ABAP.
Below is the sample piece of code to establish RFC connection(link) between Java and SAP.
DATA: REQUTEXT LIKE SY-LISEL,
      RESPTEXT LIKE SY-LISEL,
      ECHOTEXT LIKE SY-LISEL.
DATA: RFCDEST like rfcdes-rfcdest VALUE 'NONE'.
DATA: RFC_MESS(128).
REQUTEXT = 'HELLO WORLD'.
RFCDEST = 'JCOSERVER01'. "corresponds to the destination name defined in the SM59
CALL FUNCTION 'STFC_CONNECTION'
   DESTINATION RFCDEST
   EXPORTING
     REQUTEXT = REQUTEXT
   IMPORTING
     RESPTEXT = RESPTEXT
     ECHOTEXT = ECHOTEXT
   EXCEPTIONS
     SYSTEM_FAILURE        = 1 MESSAGE RFC_MESS
     COMMUNICATION_FAILURE = 2 MESSAGE RFC_MESS.
IF SY-SUBRC NE 0.
    WRITE: / 'Call STFC_CONNECTION         SY-SUBRC = ', SY-SUBRC.
    WRITE: / RFC_MESS.
ENDIF.
Regards,
Sree

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.

How to protect java program from hotspot sa

I tried several methods(eg. custom classloader、jvmti) to protected my java program from decompile. They work well until meeting hotspot sa. "Hotspot sa classdump" is so powerf that it can directly dump class from java process's memory in a non invasive debug mode, which make any protect method useless. Is there any way to protect from "hotspot sa classdump"?

There's really no secure way to protect code, in the way that you imagine.
However, your code is most likely not so important that it matters (if it were important, you would already know that it's impossible to give your code away to someone and protect it at the same time).
Of course if you provide your software as a service, the code is never executed by the client and he can't decompile it. Of course not all software can be provided as a service.

Launching a Java Program from UNIX ( C/C++ )

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