How can I call a C program in a Shell scipt from java

Hi all,
I have a C program namely NetLibExample.c.I have compiled it to get a NetLibexample executable in RHEL5. It is successfully running from the terminal itself by the syntax: ./NetLibExample
I have written a shell script to call the same.The shell script is test.sh

test.sh
cd /working/AVClient
mkdir habib_test
./NetLibExample
echo "1 image captured"

This shell is running successfully and giving me the output( a new folder habib_test and output from the C program)

I have to call the shell script from Java program.The program is like this.
TestShell.java
public class TestShell {
public static void main(String[] args) {
try{
System.out.println("I am here to test the shell correctly");
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec("/working/test.sh");
int exitVal = proc.waitFor();

}catch(Exception e){
e.printStackTrace();
System.out.println("Exception caught.........."+e.toString());
}
}
}

But when I am trying to call the shell from Java,shell is runnin g properly as I am getting the new folder created from the shell.The java program is giving a exception:
java.lang.IllegalThreadStateException: process hasn't exited
at java.lang.UNIXProcess.exitValue(UNIXProcess.java:172)
at TestShell.main(TestShell.java:27)
Exception caught............java.lang.IllegalThreadStateException: process hasn't exited

Please help me.Thanks in advance.