KlearNow Interview Questions and Answers

Q1. Explain interface and abstract class
Ans. 
Interface defines a contract for classes to implement, while abstract class provides partial implementation and can have concrete methods.
• Interface cannot have method implementations, only method signatures

• A class can implement multiple interfaces but can only inherit from one abstract class

• Abstract class can have both abstract and concrete methods

• Interfaces are used for achieving multiple inheritance in Java
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Q2. Explain if we remove static keyword from main function what will happen.
Ans. 
Removing static keyword from main function will not have any impact on the program's functionality.
• Removing static keyword from main function will not affect the program's execution.

• The main function in C/C++ is always called by the operating system, regardless of whether it is static or not.

• Static keyword in main function is optional and does not change the behavior of the program.
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Q1. Project discussion and sliding window question
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Q2. Multi threading
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Q1. Difference between HashSet and HashMap
Ans. 
HashSet is a collection of unique elements, while HashMap is a key-value pair collection.
• HashSet does not allow duplicate elements, HashMap allows duplicate values but not duplicate keys.

• HashSet uses Set interface, HashMap uses Map interface.

• Example: HashSet<String> set = new HashSet<>(); HashMap<String, Integer> map = new HashMap<>();
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