Java 语法 索引 ----- 抽象类(Abstract)

abstract class Shape
{
    public int x = 100, y = 100;
    public abstract int getArea();
}


class Rectangle extends Shape
{
    @Override 
    public int getArea()
    {
        return x * y;
    }
}

参考文献： Java Quick Syntax Reference by Mikael Olsson