I want to execute another Java program in my program. I have taken reference from [here](https://stackoverflow.com/questions/4842684/how-to-compile-run-java-program-in-another-java-program). For testing I have pasted same code as accepted answer shows.I have passed a simple HelloWorld program. Program compiles perfectly but gives Main class not found error.

Here is my code:
Server.java

```
public static void main(String args[]) {
    try {
        runProcess("javac D:\\HelloWorld.java");
        runProcess("java D:\\HelloWorld");
    } catch (Exception e) {
        e.printStackTrace();
    }
}

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());
}

```

HelloWorld.java:

```
`public static void main(String args[]){
    System.out.println("Hello World!");
}`

```

Output:
`exitValue() 0 for javac
stderr: Error: Could not find or load main class D:\HelloWorld
exitValue() 1 for java`

Compiling and running same program on CMD or IDE gives perfect output.