ParentProcess that spawns a JVM and captures its standard out and error streams

import java.io.File;

      import java.io.FileOutputStream;

      import java.io.IOException;

      

      public class ParentProcess {

      

          public static String SUBPROCESS = SubProcess.class.getName();

      

          public static void main(String[] args) {

              try {

                  System.out

                          .println("This Java process will spawn a Java sub-process using the exec() method on Runtime.");

                  System.out

                          .println("The sub-process' standard ouput and error streams will be redirected to files named");

                  System.out

                          .println("'stdout.log' and 'stderr.log' in the current directory.");

                  System.out

                          .println("The sub-process will send it's System.out and System.err to");

                  System.out.println("the file 'subprocess.log'.\n");

                  String command = buildCommandLine();

                  System.out.println("Executing '" + command + "'\n");

      

                  /*

                   * see

                   * http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Runtime.html#exec(java.lang.String)

                   */

                  Process process = Runtime.getRuntime().exec(command);

      

                  ProcessLogger errorStream = new ProcessLogger(process

                          .getErrorStream(), new FileOutputStream("stderr.log"),

                          "stderr.log");

      

                  ProcessLogger outputStream = new ProcessLogger(process

                          .getInputStream(), new FileOutputStream("stdout.log"),

                          "stdout.log");

      

                  errorStream.start();

                  outputStream.start();

      

                  System.out

                          .println("Now do a kill -QUIT to the sub-process PID and note the");

                  System.out.println("thread dump appears in the 'stdout.log'.");

                  int exitVal = process.waitFor();

                  System.out.println("exitValue " + exitVal);

              } catch (IOException e) {

                  e.printStackTrace();

              } catch (InterruptedException e) {

                  e.printStackTrace();

              }

          }

      

          private static String buildCommandLine() {

              StringBuffer cmdBuilder = new StringBuffer(System

                      .getProperty("java.home"));

              cmdBuilder.append(File.separatorChar);

              cmdBuilder.append("bin");

              cmdBuilder.append(File.separatorChar);

              cmdBuilder.append("java -cp ");

              cmdBuilder.append(System.getProperty("java.class.path"));

              cmdBuilder.append(' ');

              cmdBuilder.append(SUBPROCESS);

              String command = cmdBuilder.toString();

              return command;

          }

      

      }