Unable to build .class file through Runtime class compilation

Question

public void actionPerformed(ActionEvent e)
    {
        String sout;
        try
          {         
            if(e.getSource()==compile)
            {
            sout=input.getText();
            Runtime rt=Runtime.getRuntime();                            
Process p=rt.exec("javac sout.java",null,new     File("C:/c/compile assign"));
            }

I am storing the class name in String sout(through TextField) then calling sout.java (i.e classname.java) but it was unable to build a class file.

            if(e.getSource()==run)
            {
InputStream is = Runtime.getRuntime().exec("java input.getText()",null,new             File("C:/c/compile assign")).getInputStream();
            //BufferedInputStream b=new BufferedInputStream(is);
         BufferedReader br= new BufferedReader(new InputStreamReader(is));      
            output.setText(br.readLine()+"hello");
            }
        }
        catch(Exception e1)
        {
        e1.printStackTrace();
        }
    }

Commands to `exec` or better `ProcessBuilder` are better kept in a `String[]`. Be sure to visit the Java World article linked from the [`exec` info. page](http://stackoverflow.com/tags/runtime.exec/info). Implement all the recommendations. — Andrew Thompson, Sep 15 '12 at 11:59

Reimeus · Accepted Answer · 2012-09-15T12:33:18.537

If you're keeping the classname in a string sout as supplied in the input textfield then your output compile command should be:

Process p=rt.exec("javac " + sout + ".java", null, new File("C:/c/compile assign"));

Also your run command should be:

Runtime.getRuntime().exec("java " + input.getText(), null, new File("C:/c/compile assign")).getInputStream();

You will probably want to add further validation before using the raw value (e.g. class exists) from this field before launching the java command.

Unable to build .class file through Runtime class compilation

1 Answers1