package six_6; class dog { public String name; public dog(String name) { this.name=name; } } public class _1{ public static void main(String[]args) { dog d1=new dog("X"); dog d2=new dog("X"); String s1=d1.toString(); String s2=d2.toString(); String s3="X"; String s4="X"; } }

您好，我可以回答您的问题。根据您提供的代码，我可以看出您正在创建两个“dog”对象和四个字符串对象。在Java中，“==”运算符用于比较两个对象引用是否相等（指向同一内存地址），而“equals()”方法用于比较对象的内容是否相等。所以，对于字符串比较，建议使用“equals()”方法来比较两个字符串是否相等。

在这个例子中，由于字符串“X”在Java中是常量，在编译时会被优化为同一个对象，所以对于字符串比较，使用“==”运算符来判断它们是否相等是可以的。而对于比较两个“dog”对象，因为它们是不同的实例，所以使用“==”运算符比较将返回false。如果您想比较两个“dog”对象的内容，您需要重写“equals()”方法。

希望我的解答对您有帮助！

相关问题

续写这段代码package animal; public abstract class Animal { private String name; public Animal(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } public abstract void makeSound();

public class Cat extends Animal {
private int age;

public Cat(String name, int age) {
super(name);
this.age = age;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

@Override
public void makeSound() {
System.out.println("Meow");
}
}

public class Dog extends Animal {
private String breed;

public Dog(String name, String breed) {
super(name);
this.breed = breed;
}

public String getBreed() {
return breed;
}

public void setBreed(String breed) {
this.breed = breed;
}

@Override
public void makeSound() {
System.out.println("Woof");
}
}

public class Elephant extends Animal {
private int weight;

public Elephant(String name, int weight) {
super(name);
this.weight = weight;
}

public int getWeight() {
return weight;
}

public void setWeight(int weight) {
this.weight = weight;
}

@Override
＊＊＊

续写代码public abstract class Animal { private String name; public Animal(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } public abstract void makeSound(); } // 包 animal package animal; public class Cat extends Animal { private int age; public Cat(String name, int age) { super(name); this.age = age; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public void makeSound() { System.out.println("Meow"); } } public class Dog extends Animal { private String breed; public Dog(String name, String breed) { super(name); this.breed = breed; } public String getBreed() { return breed; } public void setBreed(String breed) { this.breed = breed; } @Override public void makeSound() { System.out.println("Woof"); } } public class Elephant extends Animal { private int weight; public Elephant(String name, int weight) { super(name); this.weight = weight; } public int getWeight() { return weight; } public void setWeight(int weight) { this.weight = weight; } @Override要求0.必须有抽象父类，且被继承 1.必须包含 >=2 个包2.必须创建 >=5 个类(其中包含抽象父类)3.类中属性皆为私有属性，需定义读写方法 4.子类需要重写个别父类方法

续写代码：

// 包 animal
package animal;

public abstract class Animal {
private String name;

public Animal(String name) {
this.name = name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public abstract void makeSound();
}

public class Cat extends Animal {
private int age;

public Cat(String name, int age) {
super(name);
this.age = age;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

@Override
public void makeSound() {
System.out.println("Meow");
}
}

public class Dog extends Animal {
private String breed;

public Dog(String name, String breed) {
super(name);
this.breed = breed;
}

public String getBreed() {
return breed;
}

public void setBreed(String breed) {
this.breed = breed;
}

@Override
public void makeSound() {
System.out.println("Woof");
}
}

public class Elephant extends Animal {
private int weight;

public Elephant(String name, int weight) {
super(name);
this.weight = weight;
}

public int getWeight() {
return weight;
}

public void setWeight(int weight) {
this.weight = weight;
}

@Override
＊＊＊