Runtime exec problem with command "start"

Question

L.S,
I'm working on a webservice client for uploading
and downloading files. When a file is downloaded, it
should be opened by the appropriate application. I
know that this is -in theory- possible by issuing a
start command through Runtime.getRuntime.exec():
public void doSomething(String realName, DataHandler handler) {
  File outFile = new File(realName);
  FileOutputStream out = new FileOutputStream(outFile);
  handler.writeTo(out);
  out.close();
  String fileName = outFile.getAbsolutePath();
  Process p = Runtime.getRuntime().exec("start " + fileName);
}Running this on my Win2000 system with J2RE 1.4.2 consistently
fails with this message:
java.io.IOException: CreateProcess: start C:\tmp\test.pdf error=2When I issue the exact same command from a DOS shell, Adobe
starts up with the test document loaded. I now believe that my own
application is somehow 'holding on to' the file, preventing an
external application like Adobe from consuming the same file.
Does anyone know how I can get around a problem like this? How do
I start the appropriate application and feed it the file that was
just downloaded by the user?

Answer 1

I did a search for Runtime.exec and found some good help in this forum. Someone posted something like the following and it works pretty well.
<<begin code>
// Determine proper shell command (extend per OS)
String os_name = System.getProperty("os.name");
String shellParam "";
if (os_name.startsWith("Windows"))
if ( (System.getProperty("os.name").endsWith("NT")) ||
(System.getProperty("os.name").endsWith("2000")) ||
(System.getProperty("os.name").endsWith("XP")) )
shell = "cmd.exe";
} else
shell = "command.com";
shellParam = "/C";
// Create a string with your program executable
String command = "myprogram.exe";
// Create an array of each command, I found that placing "cmd.exe /c"
// in the same string doesn't work.
String[] cmd_array = new String[] {
shell,
shellParam,
command
Runtime.getRuntime().exec( cmd_array );
<<end code>>
Do a java API search for Runtime.exec (if you use Eclipse right click and hit Open Declaration) there are ways to invoke exec that support setting of the environment as well as the current directory.