关于equals和hashCode

Collection中的remove和contains方法，都是挨个比较每个对象是否equals参数中的对象，如果equals了，就remove掉或者包含。

看下面例子：

package com.cy.container;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;

public class BasicContainer {
    public static void main(String[] args) {
        Collection c = new ArrayList();
        c.add("hello");
        c.add(new Name("f1", "l1"));
        c.add(new Integer(100));
        c.remove("hello");
        c.remove(new Integer(100));
        System.out.println(c.remove(new Name("f1", "l1")));
        System.out.println(c);
    }
}

class Name{
    private String firstName, lastName;
    
    public Name(String firstName, String lastName) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    @Override
    public String toString() {
        return "Name [firstName=" + firstName + ", lastName=" + lastName + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Name other = (Name) obj;
        if (firstName == null) {
            if (other.firstName != null)
                return false;
        } else if (!firstName.equals(other.firstName))
            return false;
        if (lastName == null) {
            if (other.lastName != null)
                return false;
        } else if (!lastName.equals(other.lastName))
            return false;
        return true;
    }
    
}

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