下面是一个Java SpareTire类的实例:

public class SpareTire {private int diameter;private String brand;public SpareTire(int diameter, String brand) {this.diameter = diameter;this.brand = brand;}public int getDiameter() {return diameter;}public void setDiameter(int diameter) {this.diameter = diameter;}public String getBrand() {return brand;}public void setBrand(String brand) {this.brand = brand;}public void inflate() {System.out.println("Inflating spare tire");}public void changeBrand(String newBrand) {System.out.println("Changing spare tire brand from " + brand + " to " + newBrand);this.brand = newBrand;}public static void main(String[] args) {// 创建一个SpareTire对象SpareTire spareTire = new SpareTire(16, "Goodyear");// 调用对象的方法System.out.println("Spare tire diameter: " + spareTire.getDiameter());System.out.println("Spare tire brand: " + spareTire.getBrand());spareTire.inflate();spareTire.changeBrand("Michelin");System.out.println("New spare tire brand: " + spareTire.getBrand());}}

这个SpareTire类表示一个备用轮胎,它有一个直径和品牌属性,以及一些操作这些属性的方法。在main方法中,我们创建一个SpareTire对象,并调用它的方法来获取和修改属性,并执行一些其他操作。最后,我们打印出修改后的属性值。