API Developer Interview Questions and Answers

Updated 25 Aug 2024

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Q1. What is an API and difference between rest and soap?

Ans.

API stands for Application Programming Interface. REST and SOAP are two different types of APIs.

API stands for Application Programming Interface, which allows different software applications to communicate with each other.
REST (Representational State Transfer) is an architectural style for designing networked applications, while SOAP (Simple Object Access Protocol) is a protocol for exchanging structured information in web services.
REST APIs typically use standard HTTP method...read more

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 be overwritten in the map.

Q3. 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

Q4. How apigee is used to manage api?

Ans.

Apigee is used to manage APIs by providing tools for designing, deploying, and monitoring APIs.

Apigee Edge platform allows for API design, deployment, security, and analytics.
It provides a user-friendly interface for creating and managing APIs.
Apigee Edge enables developers to easily create API proxies to connect to backend services.
It offers features like traffic management, security, and developer engagement tools.
Apigee Edge also provides analytics to monitor API performan...read more

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Q5. Describe an architecture you helped design

Ans.

Designed a microservices architecture for a banking application

Utilized Docker containers for each microservice
Implemented API Gateway for routing and load balancing
Used Kafka for asynchronous communication between services

Q6. 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 interfaces.
Encapsulation promotes data integrity and prevents una...read more

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Q7. 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 @RestController annotation is a combination of @Controller and @Resp...read more