Java.lang.String.hashCode() Method

Description

The java.lang.String.hashCode() method returns a hash code for this string. The hash code for a String object is computed as:

s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1] where, s[i] is the ith character of the string, n is the length of the string, and ^ indicates exponentiation

Declaration

Following is the declaration for java.lang.String.hashCode() method

public int hashCode()

Parameters

• NA

Return Value

This method returns a hash code value for this object.

Exception

• NA

Example

The following example shows the usage of java.lang.String.hashCode() method.

package com.tutorialspoint;

import java.lang.*;

public class StringDemo {

  public static void main(String[] args) {
  
    Integer i = new Integer(50);
    Long l = new Long(50);
    Float f = new Float(50);
    Integer i2 = new Integer(0);
    
    // hash codes of different objects with same value are always same
    System.out.println("Hash code of " + i + " is =  " + i.hashCode());
    System.out.println("Hash code of " + l + " is =  " + l.hashCode());
  
    // hash code for float value i.e different from Integer and Long
    System.out.println("Hash code of " + f + " is =  " + f.hashCode());    
        
    // hash code value of number zero(0) is zero(0)
    System.out.println("Hash code of " + i2 + " is = " + i2.hashCode());

    String str = "this is tutorialspoint";
    
    // hash code of string str
    System.out.println("Hash code of string is = " + str.hashCode());
  }
}

Let us compile and run the above program, this will produce the following result:

Hash code of 50 is = 50
Hash code of 50 is = 50
Hash code of 50.0 is = 1112014848
Hash code of 0 is = 0
Hash code of string is = 643938959