How to run Executables or .bat files from Java?

Question

Hi!
I need to open a Web Browser from Java App.
Please, help me to do this without calling JNI
-or-
provide me with sample which works with
Runtime.execute() method.
I have done full permission:
grant
     permission java.security.AllPermission "","";
};Thank You in advance!

Answer 1

To run any command from java code, the method is
Runtime.getRuntime().exec( myCommandString )
Where, myCommandString is something like "/full/pathname/command".
If the pathname contains spaces, e.g. "c:\program files\windows\notepad", then enclose it in quotes within the quoted string. Or pre-tokenize them into elements of an array and call exec(String[] cmd) instead of exec(String cmd).
From JDK1.3 there are two new overloaded Runtime.exec() methods. These allow you to specify starting directory for the child process.
Note, there is a gotcha associated with reading output from commands. When the runtime exec's the process, it passes to it 3 streams, for stdin, stdout, and stderr; the out and err are buffered but the buffer size isn't very big. When your process runs, it reads (if needed) from in, and writes to out and err.
If it doesn't write more than the buffer-size, it can run to completion.
But if it tries to write more data to one or the other stream than the buffer can hold, the write blocks, and your process hangs, waiting for you to empty the buffer so it can write some more.
So after the exec call, get the streams, and read from them in a loop until they both hit end-of-stream (don't block on either one, just read whatever is available from each, each loop iteration).
Then when the streams have ended, call the process.waitFor() method to let it finish dying.
Now, here is a code snippet how you achieve this.
String strCommand = "cmd.exe /c " + strCommand;
boolean bWait = true;
//execute the command
try
     Runtime r = Runtime.getRuntime();
     Process pr = r.exec(strCommand);
     Process pr = r.exec(callAndArgs);
     BufferedInputStream bis =new BufferedInputStream(pr.getInputStream ());
     int c=0;
     /** Outlet for IO for the process **/
     while (c!=-1)
          c=bis.read();
     /**Now wait for the process to get finished **/
     if(bWait == true)
          pr.waitFor();
          pr.destroy();
catch(Exception e)
     System.out.println("Could not execute process " + strCommand);
     return(false);