Cant solve problem

Question about the task

Resolved

javax.management.monitor.Monitor is abstract; cannot be instantiated when run it said class monitor is abstract, but i couldn't find any problem, please help.

1. Create the CompItem interface.
2. Add a String getName() method to it.
3. Create Keyboard, Mouse, and Monitor classes that implement the CompItem interface.
4. The getName() method must return the class name. For example, it will return "Keyboard" for the Keyboard class.
5. Create the Computer class.
6. Add a private Keyboard field keyboard to the Computer class.
7. Add a private Mouse field mouse to the Computer class.
8. Add a private Monitor field monitor to the Computer class.
9. Use the Alt+Insert key combination (on Windows) (Constructor command) to create a Computer class constructor with three parameters.
10. Inside the constructor, use the parameters to initialize all three of the class's fields (variables).
11. Create getters for the fields in the Computer (in the class, use the Alt+Insert key combination (on Windows) and select the Getter command).
12. Each class and interface should be in a separate file.

Requirements:

The CompItem interface must be in a separate file.
The CompItem interface must define a getName() method that returns a String and has no parameters.
The Keyboard, Monitor, and Mouse classes must implement the CompItem interface, and be located in separate files.
The getName method in classes implementing the CompItem interface should return a simple class name, e.g. "Keyboard" for the Keyboard class.
The Computer class must be in a separate file and have one private field of each of the following types: Keyboard, Mouse, and Monitor.
The Computer class constructor should have 3 parameters (keyboard, mouse, monitor) and correctly initialize the corresponding fields of the class.
For the Computer class's fields keyboard, mouse, and monitor, you need to create getters (getKeyboard, getMouse, getMonitor) that return the corresponding fields of the Computer class.

package com.codegym.task.task14.task1413; /* Computer */ import javax.management.monitor.Monitor; public class Solution { public static void main(String[] args) { Computer computer = new Computer(new Keyboard(), new Mouse(), new Monitor()); if (isWork(computer.getKeyboard()) && isWork(computer.getMonitor()) && isWork(computer.getMouse())) { System.out.println("Work!"); } } public static boolean isWork(CompItem item) { System.out.println(item.getName()); return item.getName() != null && item.getName().length() > 4; } }

Comments (5)

Popular
New
Old

You must be signed in to leave a comment

Guadalupe Gagnon

Level 37 , Tampa, United States

16 October 2019, 00:25

solution

your pulling from a completely different library. Remove the import statement.

Wei Cui

Level 39 , Newark, United States

16 October 2019, 00:51

Thanks a lot! I spend lots of time and ignore that tiny issue.

Guadalupe Gagnon

Level 37 , Tampa, United States

16 October 2019, 13:39

I've made the same mistake in the past. IntelliJ is a great tool but sometimes its "helpfulness" can hurt you. It found a Monitor class defined in that other library and tried to help you by importing the package expecting you to use it. That is a hard thing to spot when you are working with 6 different classes in your package.

Wei Cui

Level 39 , Newark, United States

16 October 2019, 13:58

when you work on project for a long time , its easy to ignore tiny parts. So do you have any suggestion or experience to help to avoid similar issue?

Guadalupe Gagnon

Level 37 , Tampa, United States

16 October 2019, 14:14

The best way to learn to avoid mistakes is to make mistakes, and then spend a lot of time figuring out why your code doesn't work. Just like this example, you will start looking at your import statements closer in the future. Do you remember looping through arrays? I remember making code like this:

for(int i = 0; i <= array.length; i++){
     doSomethingWith(array[i]);
}

That code will throw an indexOutOfRange exception when i equals the length. It took me a few times making that mistake but now it is common knowledge not to.