Writing a compiler with Compiler and Runtime class

Question

I am writing a simple compiler that uses the Compiler class to compile a program and the Runtime class to execute the java file. However, I am having trouble located the .class file, and displaying the results when the file is executed. The following code is a segment of my program. Does anyone have any suggestions?
try
               saveFile();
               //Process p = Runtime.getRuntime().exec("javac "+fileName.getName());
          Process p = null;
               //JOptionPane.showMessageDialog(null,"Compile Message "+p.getErrorStream(), "Message:                
               ",JOptionPane.ERROR_MESSAGE);
               s = fileName.getName();
               int truncStart = s.indexOf(".java");
               compiled = java.lang.Compiler.compileClasses(s);
               s = s.substring(0,truncStart);
               JOptionPane.showMessageDialog(null,"Compile File "+s, "Compile File : ",JOptionPane.ERROR_MESSAGE);
               p = Runtime.getRuntime().exec("java "+s);
          

Answer 1

OK, I think I need a delay between my compile stmt and my exec stmt. If anybody has had a similiar problem please let me know how you resolved it. Here is my code so far.
try
               saveFile();
          Process p = null;
               s = fileName.getName();
               String[] command = {"javac","c:/"+s};
               try
               JOptionPane.showMessageDialog(null,"Compile File "+s, "Compile File : ",JOptionPane.ERROR_MESSAGE);
               p = Runtime.getRuntime().exec(command);
               catch (Exception q)
               JOptionPane.showMessageDialog(null,"Compile Error:"                
+q.toString(),"Error!",JOptionPane.ERROR_MESSAGE);
               int truncStart = s.indexOf(".java");
               s = s.substring(0,truncStart);
               String[] command2 = {"java", "c:/"+s};
               try
               JOptionPane.showMessageDialog(null,"Exec. File "+s, "Exec. File : ",JOptionPane.ERROR_MESSAGE);
               p = Runtime.getRuntime().exec(command2);
               catch(Exception y)
               JOptionPane.showMessageDialog(null,"Exec Error :"+y.toString(),"Error!",JOptionPane.ERROR_MESSAGE);
               }