multiple classes in Dr. Java

The JDK compiler says it compiles, but when it runs I get this error:

Static Error: This class does not have a static void main method accepting String[].

I am used to putting my methods class in one file and putting the main class in a sperate file.

How do I go about solving this issue?

    import java.util.Scanner;

public class Test{
  private final int classSize = 35;
  private int numEnrolled, numNeeded; 

  public void Input(){
   Scanner in = new Scanner(System.in);
   System.out.println("Enter the amount enrolled in your class");
   numEnrolled = in.nextInt();
   System.out.println("Your input is " + numEnrolled);       

   // Other parts of code that needs to be coded 
  }
}

class testRunner{
  static void main(String args[]){
    Test newTest = new Test();
    newTest.Input();

 }}

• In one file you can have only one public class, and multiple non-public classes
• Your filename has to match with the only public class
• To make your class runnable it should contain a public static void main(String args[]) method, preferably in the public class

Your TestRunner.java should look like this

class Test{
    private final int classSize = 35;
    private int numEnrolled, numNeeded;

    public void Input(){
        Scanner in = new Scanner(System.in);
        System.out.println("Enter the amount enrolled in your class");
        numEnrolled = in.nextInt();
        System.out.println("Your input is " + numEnrolled);

        // Other parts of code that needs to be coded
    }
}

public class TestRunner{
    public static void main(String args[]){
        Test newTest = new Test();
        newTest.Input();

    }}

Edit: If you want to leave the file name Test.java, this works too:

public class Test {
    private final int classSize = 35;
    private int numEnrolled, numNeeded;

    public void Input() {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter the amount enrolled in your class");
        numEnrolled = in.nextInt();
        System.out.println("Your input is " + numEnrolled);

        // Other parts of code that needs to be coded
    }
}

class TestRunner {
    public static void main(String args[]) {
        Test newTest = new Test();
        newTest.Input();

    }
}