title: Error: Could not find or load main class <<< Why do I get this error?
body: <p>I can't seem to get this code to work correctly. This is the error I keep getting: </p>
  
  <blockquote>
    <p>Error: Could not find or load main class. </p>
  </blockquote>
  
  <p>What causes this?</p>
  
  <p><em>Payroll3.java</em></p>
  
  <pre><code>// A program to calculate and print the department, name, and pay of an employee.
  import java.util.Scanner; //program uses the Scanner class
  import java.io.*;
  
  class main
  {
  public class Payroll3
  
  {
  // main method begins execution of Java program.
      public void main(String args[])
            {
     // create Scanner to obtain input from the command window
     Scanner input = new Scanner (System.in);
  
     double number1; // first number to multiply
     double number2; // second number to multiply
     double product; // product of number1 and number2
  
  
  while(true){   // infinite loop
  
  
     System.out.print("Enter Department name: "); //prompt
     String name = input.nextLine(); // read name from user
  
      if(name.equals("stop"))  // exit the loop
          break;
  
  
     System.out.print("Enter number of employees: "); // prompt
     number1 = input.nextDouble(); // read first number from user
     input.nextLine();
        while( number1 &lt;= -1){
           System.out.print("Enter positive number of employees:"); // prompt
           number1 = input.nextDouble(); // read first number from user
           input.nextLine();
        } /* while statement with the condition that negative numbers are entered
           user is prompted to enter a positive number */
  
     System.out.print("Enter average salary: "); // prompt
     number2 = input.nextDouble(); // read second number from user
     input.nextLine();
        while( number2 &lt;= -1){
         System.out.print("Enter positive number for average salary:"); // prompt
          number2 = input.nextDouble(); // read first number from user
          input.nextLine();                    
   } /* while statement with the condition that negative numbers are entered
           user is prompted to enter a positive number */
  
     // make department object
          Department dept = new Department(name,number1,number2);
  
     product = number1 * number2; // multiply numbers
  
     System.out.println("Department name:" + name); // display Department name
     System.out.printf("Payroll is: $%.2f\n", product); // display product
  
     } // end while method
  
  } // end method main
  
  }/* end class Payroll3 */
  }
  
  //  Stores data about an department
  class Department {
  
  //fields
  String name;
  double number1;
  double number2;
  
  // constructor
  public Department(String name, double number1, double number2) {
      this.name = name;
      this.number1 = number1;
      this.number2 = number2;
  }
  
  // returns the pay:
  public double getPay() {
      return number1*number2;
  }
  
  // getters and setters
  
  public String getName() {
      return name;
  }
  
  public void setName(String name) {
      this.name = name;
  }
  
  public double getnumber1() {
      return number1;
  }
  
  public void setNumber1(double number1) {
      this.number1 = number1;
  }
  
  public double getNumber2() {
      return number2;
  }
  
  public void setNumber2(double number2) {
      this.number2 = number2;
  }
  
  
  }
  </code></pre>