Java Core Technology-object Hashcode

Hashcode (hash code) is an integer value exported by the object, the hash code is not regular, if the object is not the same, its hash code basically will not be consistent.

(string) The hash code of the string is the content exported, two identical contents of the string, its hash code is consistent, but the StringBuffer class does not define the Hashcode method, the object class will be the default Hashcode method to export the storage address of the objects, Therefore, even if the content of the two StringBuffer is consistent, the hash code is inconsistent.

Utils class

String str = "1"; String name = "string"; Objects.hash (str, name);//Returns a hashcode that is composed of a hash code of the provided object Objects.hashcode (str);// Returns the hashcode of the current object, or 0 if the object is null

Java Core Technology-object Hashcode