hashCode
public int hashCode()
- Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by
java.util.Hashtable.The general contract of
hashCodeis:- Whenever it is invoked on the same object more than once during an execution of a Java application, thehashCodemethod must consistently return the same integer, provided no information used inequalscomparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
- If two objects are equal according to theequals(Object)method, then calling the
hashCodemethod on each of the two objects must produce the same integer result. - It is not required that if two objects are unequal according to the
equals(java.lang.Object)method, then calling thehashCodemethod on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.
As much as is reasonably practical, the hashCode method defined by classObjectdoes return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)
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