Piping between processes, see http://blog.bensmann.com/piping-between-processes

Piper.java

public class Piper implements java.lang.Runnable {

    private java.io.InputStream input;

    private java.io.OutputStream output;

    public Piper(java.io.InputStream input, java.io.OutputStream output) {
        this.input = input;
        this.output = output;
    }

    public void run() {
        try {
            // Create 512 bytes buffer
            byte[] b = new byte[512];
            int read = 1;
            // As long as data is read; -1 means EOF
            while (read > -1) {
                // Read bytes into buffer
                read = input.read(b, 0, b.length);
                //System.out.println("read: " + new String(b));
                if (read > -1) {
                    // Write bytes to output
                    output.write(b, 0, read);
                }
            }
        } catch (Exception e) {
            // Something happened while reading or writing streams; pipe is broken
            throw new RuntimeException("Broken pipe", e);
        } finally {
            try {
                input.close();
            } catch (Exception e) {
            }
            try {
                output.close();
            } catch (Exception e) {
            }
        }
    }
    
    public static java.io.InputStream pipe(java.lang.Process... proc) throws java.lang.InterruptedException {
        // Start Piper between all processes
        java.lang.Process p1;
        java.lang.Process p2;
        for (int i = 0; i < proc.length; i++) {
            p1 = proc[i];
            // If there's one more process
            if (i + 1 < proc.length) {
                p2 = proc[i + 1];
                // Start piper
                new Thread(new Piper(p1.getInputStream(), p2.getOutputStream())).start();
            }
        }
        java.lang.Process last = proc[proc.length - 1];
        // Wait for last process in chain; may throw InterruptedException
        last.waitFor();
        // Return its InputStream
        return last.getInputStream();
    }
    
}

PipeTest.java

public class PipeTest {

    public static void main(String[] args) throws java.io.IOException, java.lang.InterruptedException {
        java.lang.Runtime rt = java.lang.Runtime.getRuntime();
        // Start three processes: ps ax | grep rbe | grep JavaVM
        java.lang.Process p1 = rt.exec("ps ax");
        java.lang.Process p2 = rt.exec("grep rbe");
        java.lang.Process p3 = rt.exec("grep JavaVM");
        // Start piping
        java.io.InputStream in = Piper.pipe(p1, p2, p3);
        // Show output of last process
        java.io.BufferedReader r = new java.io.BufferedReader(new java.io.InputStreamReader(in));
        String s = null;
        while ((s = r.readLine()) != null) {
            System.out.println(s);
        }
    }

}