How do I Pipe process output to a file on Windows and JDK 6u45

Question

I have the following windows batch file (run.bat):

@echo off
echo hello batch file to sysout

And the following java code, which runs the batch files and redirects output to a file:

public static void main(String[] args) throws IOException {
    System.out.println("Current java version is: " + System.getProperty("java.version"));

    ProcessBuilder pb =
            new ProcessBuilder("cmd.exe", "/c",
                    "run.bat"
                     ,">>", "stdout.txt","2>>", "stderr.txt"
                    );
    System.out.println("Command is: " + pb.command());

    Process proc = pb.start();

    InputStream in = proc.getInputStream();
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));

    String line = null;
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
    }

    int exitValue = proc.exitValue();
    System.out.println("Exit value: " + exitValue);
}

On JDKs up to and including JDK6u43 I get the following output:

Current java version is: 1.6.0_29
Command is: [cmd.exe, /c, run.bat, >>, stdout.txt, 2>>, stderr.txt]
Exit value: 0

and the script output is written to the file. As of JDK 6u45 and 7, I get the following output:

Current java version is: 1.6.0_45
Command is: [cmd.exe, /c, run.bat, >>, stdout.txt, 2>>, stderr.txt]
hello batch file to sysout
Exit value: 0

And nothing is written to the output file.

This may or may not be related to the changes made in Runtime.exec() , described at: http://www.oracle.com/technetwork/java/javase/6u45-relnotes-1932876.html

What is the correct way of starting a process on Windows with output redirected to files?

Note: In a real world scenario, the command to execute may include parameters with spaces, as in:

ProcessBuilder pb = new ProcessBuilder("cmd.exe", "/c",
"run.bat", "Some Input With Spaces", 
">>", "stdout.txt","2>>", "stderr.txt");

Answer 1

This is the simplest method i found on http://tamanmohamed.blogspot.in/2012/06/jdk7-processbuilder-and-how-redirecting.html

File output = new File("C:/PBExample/ProcessLog.txt");
ProcessBuilder pb = new ProcessBuilder("cmd");
pb.redirectOutput(output);