It's all about Stream...

Question

Hi' this is really makes me feel so upset. Why every time i try to execute WindowsExec file.
There's no error in code but the output not correctly.
WindowsExec.java :
public class WindowsExec
     response std_out,std_err;
     DataOutputStream doStream;
     outputer std_in;
     public WindowsExec()
          try
               String[] cmd = new String[]{"cmd.exe","/C","java","maintest"};
            Runtime rt = Runtime.getRuntime();
               Process proc = rt.exec(cmd);
               std_out = new response(proc.getInputStream(),System.out);          
               std_err = new response(proc.getErrorStream(),System.err);
               doStream = new DataOutputStream(proc.getOutputStream());
               std_in = new outputer(doStream);
               std_out.start();
               std_err.start();     
               std_in.start();
               int exitVal = proc.waitFor();
            System.out.println("ExitValue: " + exitVal);
               proc.destroy();
               doStream.close();     
          catch (Throwable t)
             t.printStackTrace();
    public static void main(String args[])
          new WindowsExec();
outputer.java :
class outputer extends Thread
     OutputStream write;
     BufferedReader bfr;
     public outputer(OutputStream write)
          try
               this.write = write;
          catch(Exception e)
               e.printStackTrace();
     public void run()
          try
               bfr = new BufferedReader(new InputStreamReader(System.in));
               String input = null;
               input = bfr.readLine();
               write.write(input.getBytes());     
               write.flush();
               write.close();
               bfr.close();          
          catch(Exception e)
               e.printStackTrace();
response.java
class response extends Thread
     InputStream is;
     PrintStream type;
     public response(InputStream is, PrintStream type)
          this.is = is;
          this.type = type;
     public void run()
          try
               InputStreamReader isr = new InputStreamReader(is);
                      BufferedReader br = new BufferedReader(isr);
                      String line = null;
                      while ( (line = br.readLine()) != null)
                                      System.out.println(line);   
               br.close();
               isr.close();
               is.close();
          catch (Exception ioe)
                        ioe.printStackTrace(); 
maintest.java
public class maintest
     public maintest()
          try
               BufferedReader bfr = new BufferedReader(new InputStreamReader(System.in));
               System.out.print("Insert : ");
               String getWord = bfr.readLine();
               System.out.println(getWord);
          catch(Exception e)
               e.printStackTrace();
     public static void main(String[] args)
          new maintest();
}This is the illustration :
1. Execute WindowsExec
2. Maintest executed from WindowsExec. (see WindowsExec source).
3. Display the output.
The output should be like this : (see maintest source to check)
1. Print Insert : and wait input from user.
2. User write some input and press enter.
3. Read input from user and display it.
4. Program terminate.
But what i got, the output are like this : (this is not correctly)
1. Wait input from user. (see maintest source,the firstline should be print "Insert :",not waiting some input).
2. User write some input and press enter
3. print Insert : and read input from user and display it.
4. Program terminate.
Why the output become like that? (Conversation between WindowsExec and maintest not correctly).
Insert : should appear in the first line of the output.
How to get the right conversation between WindowsExec and maintest?
I hope my question easy to understand.
Thanks....

Answer 1

i still got the same output. Before you set the
classpath in linux.,did my WindowsExec give the right
output?
Of course not! That is why I had to set the classpath so that java could find the maintest class.
Have you tried the simplistic approach String[] cmd = {"java",  "maintest"};
String[] env = {"CLASSPATH=" + System.getProperty("java.class.path")};
Process proc = Runtime.getRuntime().exec(cmd,env);of course, this assumes that your jdk bin directory is on the PATH (not CLASSPATH) so that java --version should run. You could start with something simple like
String[] cmd = {"java",  "-version"};
String[] env = {"CLASSPATH=" + System.getProperty("java.class.path")};
Process proc = Runtime.getRuntime().exec(cmd,env);just to prove you are picking up java!
To make sure we are talking the same language -public class WindowsExec
    response std_out,std_err;
    DataOutputStream doStream;
    outputer std_in;
    public WindowsExec()
        try
            //String[] cmd = {"sh","-c","java -classpath " + System.getProperty("java.class.path") + " me.sabre150.research.scratch.maintest"};
            String[] cmd = {"sh","-c","java me.sabre150.research.scratch.maintest"};
            String[] env = {"CLASSPATH=" + System.getProperty("java.class.path")};
            Process proc = Runtime.getRuntime().exec(cmd, env);
            std_out = new response(proc.getInputStream(),System.out);
            std_out.start();
            std_err = new response(proc.getErrorStream(),System.err);
            std_err.start();
            doStream = new DataOutputStream(proc.getOutputStream());
            std_in = new outputer(doStream);
            std_in.start();
            int exitVal = proc.waitFor();
            System.out.println("ExitValue: " + exitVal);
            proc.destroy();
            doStream.close();
        catch (Throwable t)
            t.printStackTrace();
    public static void main(String args[])
        new WindowsExec();
}Message was edited by:
sabre150