Win a copy of Spring in Action (5th edition) this week in the Spring forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Bear Bibeault
  • Devaka Cooray
  • Liutauras Vilda
  • Jeanne Boyarsky
Sheriffs:
  • Knute Snortum
  • Junilu Lacar
  • paul wheaton
Saloon Keepers:
  • Ganesh Patekar
  • Frits Walraven
  • Tim Moores
  • Ron McLeod
  • Carey Brown
Bartenders:
  • Stephan van Hulst
  • salvin francis
  • Tim Holloway

The hashCode() method of java.lang.Object  RSS feed

 
Ranch Hand
Posts: 127
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
consider the following code:

public class Test
{
public static void main(String args[])
{
}
int i;
public boolean equals(Object o)//line1
{
Test t = (Test)o;//line2
if (t.i == this.i)//line3
return true;//line4
return false;//line5
}
public int hashCode() //line6
{
return i * 31;//line7
}

}

On the above program i have some queries:
1.What does it mean to declare (Object o) in line1
2.What does it mean to declare Test t = (Test)o; in line2
3.What does it mean to declare if (t.i == this.i) in line3
4.What does it mean to declare return true; in line4
5.What does it mean to declare return false; in line5
6.what is the need in this program to implement hashCode() method
7.What is the need of hashCode() method to return i*31;why in particular i*31 value is returned

i would be very thankful if i get the queries to be solved.

tx
carl
 
Ranch Hand
Posts: 8934
Firefox Browser Java Spring
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Read this tutorial
http://www.jchq.net/certkey/0902certkey.htm
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!