构造方法，方法重载

默认构造方法无参数

带参数的构造方法进行初始化

重载参数不同

public class Tree {static int height;Tree(){System.out.println("Plant a seedling");}Tree(int initialHeight){height = initialHeight;System.out.println("Create new Tree that is "+height+" feet tall");}void info(){System.out.println("Tree is "+height+" feet tall");}void info(String s){System.out.println(s+":Tree is "+height+" feet tall");}public static void main(String[] args) {for(int i = 0 ; i < 5 ; i++){Tree t = new Tree(i);t.info();t.info("overloaded method");}new Tree();System.out.println(height);}}