CreateProcess error 2 The system cannot find the file specified

Question

I have written a java program to unzip a jar file.

My code looks like this:

import java.io.File;
import java.io.IOException;

public class MainClass {

    public static void main(String[] args) {

        Runtime r = Runtime.getRuntime();
        Process p = null;

        try {
            File dir = new File("C:/Program Files/WinRAR");
            p = r.exec("winrar x h:\\myjar.jar *.* h:\\new", null, dir);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

When I run this, I am getting this error:

java.io.IOException: Cannot run program "winrar" (in directory "C:\Program Files\WinRAR"): CreateProcess error=2, The system cannot find the file specified
    at java.lang.ProcessBuilder.start(Unknown Source)
    at java.lang.Runtime.exec(Unknown Source)
    at java.lang.Runtime.exec(Unknown Source)
    at MainClass.main(MainClass.java:16)
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified
    at java.lang.ProcessImpl.create(Native Method)
    at java.lang.ProcessImpl.<init>(Unknown Source)
    at java.lang.ProcessImpl.start(Unknown Source)
    ... 4 more

Can someone tell me why this error occurred? and please guide me to fix this issue.