How to change path while running java file?

Question

I am trying to run a java file through another java program . this is my code:

private static void printLines(String name, InputStream ins) throws Exception {     
        String line = null;
        BufferedReader in = new BufferedReader(
            new InputStreamReader(ins));
        while ((line = in.readLine()) != null) {
            System.out.println(name + " " + line);
        }
      }

      private static void runProcess(String command) throws Exception {
        Process pro = Runtime.getRuntime().exec(command);
        printLines(command + " stdout:", pro.getInputStream());
        printLines(command + " stderr:", pro.getErrorStream());
        pro.waitFor();
        System.out.println(command + " exitValue() " + pro.exitValue());
      }

      public static void main(String[] args) {
          String[] credentials=new String[4];int k=0;
          for (String s: args) {
              System.out.println(s);
            credentials[k]=s;k++;
        if(k==4)
        break;
          }
        try {
          //runProcess("javac test2.java");
          runProcess("java test2 "+credentials[0]+" "+credentials[1]+" "+credentials[2]+" "+credentials[3]+" ");

        } catch (Exception e) {
          e.printStackTrace();
        }System.out.println("hI");
      }

The problem is I have kept both the files(which I execute and the one which is executed by that file) in same folder but when I run this file it displays class not found error.. for test2.java and it probably due to the fact that it searches the class file test2.class in some other folder . what should I do? my file structure:
x/y/Laj.java
x/y/test2.java
and it seaches the class file in x folder?

Answer 1

Use

Runtime.getRuntime().exec(command, null, workingDir);

where workingDir is :

workingDir- the working directory of the subprocess, or null if the subprocess should inherit the working directory of the current process.

Answer 2

If you run the first program using

java x.y.Laj

then you should change the line where you compose the command:

runProcess("java x.y.test2 "+credentials[0]+...

** Later **

Since the xy is just a red herring, try setting the system property:

runProcess("java  -Djava.class.path=\"/.../x/y\" " + credentials[0]+...

For production (start of Laj not from an IDE) consider setting CLASSPATH so that all class files can be found via the class path.