Barclays Java Developer Interview Questions and Answers

Java and sql questions

Q1. Basics of java ans core java
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Q1. Why string is immutable
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String is immutable in Java to ensure thread safety, security, and optimization.
• Immutable strings are thread-safe as they cannot be modified concurrently by multiple threads.

• String pooling is possible due to immutability, saving memory and improving performance.

• Security is enhanced as sensitive information stored in strings cannot be altered.

• Examples: String str = "Hello"; str.concat(" World"); // str remains "Hello"
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Q2. What is spring aop
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Spring AOP (Aspect-Oriented Programming) is a framework that provides cross-cutting concerns in a modular way.
• Spring AOP allows separating cross-cutting concerns from the main application logic.

• It enables developers to define aspects (cross-cutting concerns) separately and apply them to multiple classes.

• Examples of cross-cutting concerns include logging, security, and transaction management.
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MCQ assignment based on the Java skills

Q1. It was a 1 hr 15 min of Technical round
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Q1. Scenerio based questions - duration 1 hr
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General questions on collections

Q1. Design of REST API
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Designing a REST API involves defining endpoints, methods, request/response formats, authentication, and versioning.
• Define clear and consistent endpoint URLs for resources (e.g. /users, /products)

• Use HTTP methods (GET, POST, PUT, DELETE) to perform CRUD operations on resources

• Choose appropriate response formats like JSON or XML

• Implement authentication and authorization mechanisms (e.g. OAuth, JWT)

• Consider versioning to...read more
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