Abstract Classes??? Creating a new object????

[jonytek]

I am having trouble creating new objects in abstract classes? Basically I am gettin a error - "Exception in thread "main" java.lang.Error: Unresolved compilation problems:
Cannot instantiate the type Car
Cannot instantiate the type Truck
Cannot instantiate the type Car

at Tester.main(Tester.java:6)"

Could someone help me out?

Thanks.

Code below.

public abstract class Vehicle {
	private double regoCost;
	private int regoNumber;
	private int yearManufactured;
	private int currentYear = 2010;
	
	public Vehicle(int yearManufactured, int regoNumber)
	{
		this.yearManufactured = yearManufactured;
		this.regoNumber = regoNumber;
	}
	public boolean regoCheck()
	{
		int vehicleAge = this.yearManufactured - currentYear;
		if (vehicleAge > 4)
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	public void setRegoCost(double regoCost) 
	{
		this.regoCost = regoCost;
	}
	public String toString()
	{
		return this.regoNumber + 
		" " +
		this.regoCost + 
		" " + 
		this.yearManufactured +
		" ";
	}
	public abstract int getRegoCost();
}

public abstract class Car extends Vehicle{
	private String usageType;
	
	public Car(int regoNumber, int yearManufactured, String usageType)
	{
		super(regoNumber, yearManufactured);
		this.usageType = usageType;
	}
	public int getRegCost()
	{
		if (usageType.equals("Business"))
		{
			super.setRegoCost(50);
		}
		else if (usageType.equals("Private"))
		{
			super.setRegoCost(300);
		}
		return this.getRegoCost();
	}
	public String toString()
	{
		return super.toString() + 
		" " +
		this.usageType;
	}
}

public abstract class Truck extends Vehicle{
	private int weight;
	
	private Truck(int regoNumber, int yearManufactured, int weight)
	{
		super(regoNumber, yearManufactured);
		this.weight = weight;
	}
	public int getRegCost()
	{
		if (weight < 5000)
		{
			super.setRegoCost(300);
		}
		else if (weight > 5000)
		{
			super.setRegoCost(400);
		}
		return this.getRegoCost();
	}
	public String toString()
	{
		return super.toString() +
		" " + 
		this.weight;
	}
}

public class Tester {
	public static void main(String[]args)
	{
		Vehicle[] vehicles = new Vehicle[3];
		Car porsche = new Car(12345, 2006, "Business");
		Truck mac = new Truck(666777, 1985, 10000);
		Vehicle v = new Car();
		vehicles[0] = porsche;
		vehicles[1] = mac;
		vehicles[2] = v;
		
		for (int i =0; i < vehicles.length; i++)
		{
			System.out.println(vehicles[i]);
		}
		
		/*Vehicle vp;
		
		Car ca = new Car(12345, 2006, "Business");
		vp = ca;*/
	}
}

[gcalvin]

You cannot instantiate an abstract class.

Abstract Methods and Classes (The Java™ Tutorials > Learning the Java Language > Interfaces and Inheritance)

Hint: Since Car and Truck don't have any abstract methods, they probably don't need to be abstract classes.

-Gary-

[jonytek]

Oh ok. I actually had a typo in the getRegoCost() methods so eclipse was forcing me to create Truck and Car classes as abstract. Got it working now.... Thanks for the help Gary...