Total noob here, i'm getting an error

I'm trying to run the code below in Eclipse and I'm getting the error message "Selection does not contain an applet" if I run it as an applet, and "Selection does not contain a main type" if I run it as an application. How do I fix this? I'm entirely new to java (only've done PHP and javascript, if those even count), so extra detail is more than welcome.

Code:

Code:

---

package svidler.net;

public class Cube {
        //fields
        int length;
        int breadth;
        int height;
        public int getVolume(){
                return (length * breadth * height);
        }
}

cubeObject.length = 4;
cubeObject.breadth = 4;
cubeObject.height = 4;
cubeObject.getvolume();

---

Screenshots:
http://i367.photobucket.com/albums/o...8at73149PM.png
http://i367.photobucket.com/albums/o...8at73133PM.png

You're trying to call code outside of a method or constructor, heck it's even completely outside of the class. Programs must be constructed in a structured way, and before you can start writing programs, you must understand this structure -- there unfortunately are no shortcuts. Please re-review your notes and texts to see how to construct a simple Java program. Surely these references will have a sample program that you can use as a basis for your program.

Que tenga suerte!

I took a look at some example codes and I think I understand the structure more now. I changed the code to:

Code:

---

package svidler.net;


public class Cube {
        //fields
        int length;
        int breadth;
        int height;
        public int getVolume(){
                return (length * breadth * height);
        }
        public static void main(String args[]) {
                Cube.length = 4;
                Cube.breadth = 4;
                Cube.height = 4;
                Cube.getvolume();
        }
}

---

Everything seems to be fine except for where I have "Cube.length=4; Cube.breadth = 4; ...." And I get a message, "Description Resource Path Location Type
Cannot make a static reference to the non-static field Cube.length Cube.java /First Project/src/svidler/net line 13 Java Problem
", for all 4 of those lines (13, 14, 15, 16).

You're getting closer as now you have code enclosed within methods, but you'll need to learn what an object is and how to create them. The main method is a static method and while it is part of your Cube class, it is not a method of of a Cube object, and all non-static variables and methods of Cube are not directly accessable by main or any other static method.

What you want to do instead is to create a Cube object within the main method, and then set the fields (also known as the variables) of this object.

For example:

Code:

---

public class MyClass {
  //fields
  int value;
  public int myMethod() {
      return value;
  }
  public static void main(String args[]) {
      // first create an object of the class:
      MyClass myObject = new MyClass();

      // then you can access the object's fields
      myObject.value = 3;

      // and its methods:
      System.out.println("value = " + myObject.myMethod());
  }
}

---

Later you'll not want to fiddle with an object's fields directly but rather in very controlled ways such ais via constructor parameters.

I tried doing this:

Code:

---

package svidler.net;


public class Cube {
        //fields
        int length;
        int breadth;
        int height;
        public int getVolume(){
                return (length * breadth * height);
        }
        public static void main(String args[]) {
                Cube mycube = new Cube();
                mycube.length = 4;
                mycube.breadth = 4;
                mycube.height = 4;
                mycube.getVolume();
        }
}

---

how would I know if it works?

This method:

Code:

---

mycube.getVolume();

---

returns an int. If this were my program, I'd print out the int using System.out.println(...) to see if the results match my expectations.

Thanks! You've helped me a ton!