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

Question

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

Answer 1

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