Core java - Interview Questions and Answers for 'Centurylink' | Search Interview Question

Core java - Interview Questions and Answers for 'Centurylink' - 4 question(s) found - Order By Newest

Frequently asked in high end product companies. Frequently asked in Deloitte.

Q1. How is Hashmap internally implemented in Java ?

Ans. https://medium.com/javarevisited/internal-working-of-hashmap-in-java-97aeac3c7beb#:~:text=HashMap%20internally%20uses%20HashTable%20implementation,the%20entries%20into%20the%20map.

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Q2. What is the use of HashCode in objects ?

Core Java

Ans. Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc.

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Q3. What is a shutdown hook ?

Core Java

Ans. Shutdown hook is a thread that is invoked implicitly by JVM just before the shut down. It is used to clean up unused resources.

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Q4. Write a Program to validate an email address

Core Java

Ans. public class Class{
public static void main(String[] args){
String str = "xyz@123.com";

if(!str.contains("@") && !str.contains(".") && (str.indexOf('.') < str.indexOf('@'))){
System.out.println("Not a Valid Email Address");
}
}
}

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