Air India API Developer Interview Questions, Process, and Tips

Hackathon First Round

Q1. Diff between abstraction and encapsulation
Ans. 
Abstraction focuses on hiding unnecessary details, while encapsulation bundles data and methods together.
• Abstraction is about providing a simplified view of an object or system.

• Encapsulation is about bundling data and methods within a class or object.

• Abstraction hides unnecessary details, while encapsulation protects data from direct access.

• Abstraction allows users to interact with complex systems using simpler interfa...read more
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Q2. Can we add object base class as key in hash map
Ans. 
Yes, we can add an object base class as a key in a hash map.
• In Java, any object can be used as a key in a HashMap as long as it overrides the equals() and hashCode() methods.

• The object's hashCode() method is used to determine the bucket where the key-value pair will be stored.

• The equals() method is used to compare keys for equality.

• If two keys are equal according to the equals() method, their corresponding values will
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Q3. Diff between @Controller and @RestController
Ans. 
The @Controller annotation is used to define a controller class in Spring MVC, while the @RestController annotation is used to define a RESTful controller class.
• The @Controller annotation is used for traditional MVC applications, where the response can be a view or a JSON/XML response.

• The @RestController annotation is used for building RESTful web services, where the response is always in JSON/XML format.

• The @RestContr...read more
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Q4. Java 8 code to get a list of Strings with "s" from list of names
Ans. 
Java 8 code to filter a list of names and get a new list of strings containing names with 's'.
• Use Java 8 Stream API to filter the list of names

• Use the filter() method to check if each name contains 's'

• Collect the filtered names into a new list using the collect() method
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