如何在Java中比较两个实例？

Object obj1 = new Object();
Object obj2 = obj1;
System.out.println(obj1 == obj2); // 输出: true，因为obj1和obj2指向同一个对象

String str1 = "Hello";
String str2 = "Hello";
System.out.println(str1.equals(str2)); // 输出: true，因为str1和str2的内容相同

public class Person {
    private String name;
    private int age;

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

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null || getClass() != obj.getClass()) return false;
        Person person = (Person) obj;
        return age == person.age && Objects.equals(name, person.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }
}