Java String hashCode Example

String class hashCode method example

String class hashCode method example:- This example demonstrates the working of hashCode method. this method returns corresponding hashCodes of objects value passed.

Syntax:-hashCode()

Here is the code:-

 /**
* @(#) HashCodeString.java
* HashCodeString class demonstrates the working of hashCode() method of String class of lang package
* @version 16-May-2008
* @author Rose India Team
*/


public class HashCodeString {
public static void main(String args[]) {

  // hashCode method generates hash codes repersentations of only objects
  // values
  // arithmetically hash Codes of numbers are generated as follows
  // s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
  // here i is any character value or number value of the object,
  // n is .length method value of the object say String, and ^ denotes
  // exponentiation.
  // The hash value of the empty string is zero
  Integer j = new Integer(10);
  Long k = new Long(10);
  Integer v = new Integer(0);
  // here value types don't match therefore methos returns false
  System.out.println("false is returned:  " + j.equals(k));
  // hash codes of different objects with same value are always same
  System.out.println("Hash code of number 10 is:  " + j.hashCode()
      + "\nHash code of number 10 is:  " + k.hashCode());
  // corresponding hash code value of number zero(0) is zero(0)
  System.out.println("Method returns zero: " + v.hashCode());

  String baadshah = "latter in time there will be my empire every where";
  // hashCode representation of the value ofobject 'baadshah'
  // every object has its own hash code representation of their values
  // every value of any object consists of unique hash codes
  System.out.println("Corresponding hash code value returned is:  "
      + baadshah.hashCode());
}

}

Output of the program:-

false is returned: false Hash code of number 10 is: 10 Hash code of number 10 is: 10 Method returns zero: 0 Corresponding hash code value returned is: 342164105