Talk about your understanding of hashcode and equals methods?

One 、 effect

hashCode() To get hash code , Also known as hash code ; It actually returns a int Integers . The function of this hash code is to determine the index position of the object in the hash table .

equals Its function is to judge whether two objects are equal , If the object overrides equals() Method , Compare the contents of two objects to see if they are equal ; If you don't rewrite it , Compare the addresses of two objects , Equivalent to “==”.

Two 、 usage

When storing elements into a hash table , Will call the object first hashCode Method , Calculate the storage location of the object in the hash table , If there is no element in this position, it is directly stored , If there is an element in this position, there is a hash conflict , At this time, the... Of the object will be called equals Method , Compare whether the two objects are the same , If equals Method returns true, Then the second object will not be stored in the hash table , If you return false, Will be deposited .