Interested to Buy Any Domain ? << Click Here >> for more details...
7) Suppose there is Student class like
class student {
int age;
string name;
}
We want to store these objects in a HashMap. Do we need to
override any methods in Student class? If any which ones
and why? what if i just override equals or just hashcode?
what will be the results in both the cases?
- 4 Answers
- 9310 Views
- CSC, Nagarro, RBS, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / manoranjan
Logically no need to override any method but problem with
this design will be that we can not find the objects stored
in the hashmap. So to overcome this problem we need to
override equlas() and hashcode() mathod of Object
class.According to Sun java guide line if equals() method is
teeling that two objects are equal then their hashcode must
be same.But reverse is not true.
| Is This Answer Correct ? | 10 Yes | 0 No |
Answer / lucky singh
It is a good practice to override equals() and hashcode()
methods if you are dealing with collections. Both of the
functions are used while searching for a particular object
in a hashmap. In general, equals() method is used to
determine if two objects are meaningfully equal or not. And
hashcode() method is used to determine if two objects are
meaningfully unequal or not.
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / krishna
There is no need to override equals() and hashCode() methods. But if we want to eliminate duplicate objects in the HashMap, you should override both the methods. Either one is not enough.
| Is This Answer Correct ? | 0 Yes | 0 No |
Answer / punch
Their is NO need to override any methods of student class,
bcoz in the ket of hashmap we are using String and equal
method and hashcode method of String class is already
overrided . So NO need to override any methods and take help
of String class of the same.
| Is This Answer Correct ? | 1 Yes | 7 No |
what is singleton class in java?
Mention a package that is used for linked list class in java.
What is the string function?
what is ejb? what is the importance of ejb?
Nested classes VS Inner classes?
Can we force garbage collector to run ?
What is purpose of keyword void?
What is difference between class and object in java?
What is the purpose of the finally clause?
What are implicit objects in java?
What is the scope or life time of instance variables?
what is polymorhism what is inheritance? what is Abstract n Interface? what if two interfaces have same method and a concrete class is implementing both the interfaces. Will there be a compilation error? What are mutable and immutable classes? How can u make a class mutable? when will u use dem ...explain with example? what is overriding and overloading? what is garbage collection? what is Thread? how do dey communicate? what are the different ways of implementing ? have u used any messaging technologies? what is synchronization? what are some additions in java 1.5? what are generics? whst is advanced for loop? what is finally block? can u have a try in finally? yes!! can u have a finally in finally? how do you write junits? when is a object eligible for garbage collection?explain? a = null and b has ref to a will b be eligible to be garbage collected? sql questions like diff joins? how do dey work? exception handling? what is marker interface? what is the need??
Core Java 
