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05: Web patterns interview Q&A

Q1. What do you know about model 0, model 1 and model 2 MVC design patterns? A1. In the model 0 pattern, which is also known as the model-less pattern, business logic is embedded in the JSP pages. The model 0 pattern is fine for a very basic JSP page,…

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06: Web design patterns MVC2, MVP, MVVM & MVW

Q1. What’s wrong with Servlets? What is a JSP? What is it used for? What do you know about model 0 (aka MVC0), model 1 (aka MVC1) and model 2 (aka MVC2) patterns? In “model 2” architecture, if you set a request attribute in your JSP, would you be able…

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06: Q25 – Q32 SOLID design principles interview questions & answers for Java developers

Design principles interview questions & answers for Java developers so that you can expand your OOP skills to design robust Java apps Q25. What are the SOLID design principles? A25. SOLID is an abbreviation for 5 design principles. SRP (Single Responsibility Principle) If you have a class with calculation logic,…

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06: RESTful Web services and HATEOAS Q&A

Q1. What is HATEOAS? How does it provide state transition, scalability, and loose coupling? A1. HATEOAS (Hypermedia as the Engine of Application State) is considered the final level of REST. This means that each link is presumed to implement the standard REST verbs of GET, POST, PUT, and DELETE (or…

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08: REST constraints (i.e. design rules) interview Q&A

Q1. What are the 6 REST constraints? A1. REST constraints are design rules that are applied to establish the distinct characteristics of the REST architectural style. These constraints don’t dictate what kind of technology to use, and they only define how data is transferred between components and what benefits we…

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10 ERD (Entity-Relationship Diagrams) Interview Q&As

Q01. Can you describe a business domain of a Telecom company offering multiple services to its customers? A01. A Telecom company will have entities such as Customer, Account, Subscriptions & Products representing a business domain. 1) Each customer entity has a name, physical address, and an email address. 2) A…

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10+ Domain Driven Design (i.e. DDD) Interview Q&As

Q1. What is Domain Driven Design (i.e. DDD)? What is DDD oriented microservice? A1. Domain-driven design advocates modelling based on the reality of business as relevant to your use cases. In the context of building applications, DDD talks about problems as domains. If you are building a shopping cart application,…

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11 “In your Java experience” interview questions & answers

Q1. In your Java experience, what are some of the common dilemmas you face when writing unit tests? A1. Whether to fix the code or the test. When you write unit tests, sometimes you feel compelled to change your code just to facilitate the test. For example, when you need…

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12 UML interview Q&As

Q1. What are the different types of UML diagrams? A1. Use case diagrams, Class diagrams, Package diagrams, Object diagrams, Sequence diagrams, Collaboration diagrams, and State chart diagrams. Q2. What is a use case diagram, and when will you use it? A2. Depicts the typical interaction between external users (i.e. actors)…

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15 Security key area interview Q&A for Java developers

Q1. Can you provide a high level overview of the “access control security” in a recent application you had worked? A1. As shown below, SiteMinder is configured to intercept the calls to authenticate the user. Once the user is authenticated, a HTTP header “SM_USER” is added with the authenticated user…

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16: Q114 – Q115 CAP theorem interview Q&As

Q114. What does CAP stand for in CAP theorem? A114. In a distributed system having two or more nodes, and maintaining two or more copies of your data for fault tolerance, the CAP theorem can be depicted & explained as below: Consistency – Every read should give the most recent…

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3 key “How would you go about …” Q&As to judge Java experience

Q1. How would you go about judging the code quality of other developers? A1. 1) Code written with unit tests and progressively re-factored where necessary to make it more maintainable, testable, and readable. 2) Unit tests need to be written properly — mock objects using frameworks like Mockito and Power…

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4 FAQ Performance tuning in Java interview Q&As

Q1. In your experience, what are some of the major causes of performance bottlenecks in Java applications? A1. Cause #1: The JVM spends more time performing garbage collection due to improper Garbage Collection (GC) configuration. E.g. Young generation being too small. Heap size is too small (use -Xmx). The application…

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5 Java concurrency management interview Q&As

Concurrency is very important in any modern system, and this is one topic many software engineers struggle to have a good grasp. The complexity in concurrency programming stems from the fact that the threads often need to operate on the common data. Each thread has its own sequence of execution,…

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6 Scaling your Java applications interview Q&As

Q1. What is the difference between performance and scalability? A1. The performance and scalability are two different things. For example, if you are in the business of transporting people in a van, the performance is all about utilizing more powerful engine to transporting your people quicker to their destination. Scalability…

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9 Java Transaction Management Interview Q&As

Q1. What is a Transaction? A1. A transaction is a set of operations that should be completed as a unit. If one operation fails then all the other operations fail as well. Example 1: If you transfer funds between two accounts there will be two operations in the set Operation…

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Auditing database record changes in Oracle

Q. What are some of the considerations in auditing database table data? A. Creating audit tables without any constraints to store record changes.  Audit tables are heavily hit with inserts, hence needs to have fewer indices if at all required. Decide on what combination of triggers are required like  Create,…

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How to write internationalized Java applications?

This post answers questions like — How to write internationalized Java applications? What do you understand by the terms internationalization (i18n) and localization (l10n) relating to Java programming? What is a ResourceBundle?

Localization (aka i10n, where 10 is the number of letters between the letter ‘i’ and the letter ‘n’ in the word localization ) refers to the adaptation of an application or a component to meet the language, cultural and other requirements to a specific locale (i.e.… Read more ...

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QoS & SLAs interview Q&As on Availability, Serviceability, Fault tolerance & Disaster Recoverability – Non Functional Requirements

Q1. What are the system qualities that typically form a basis for QoS requirements? A1. Quality of service (QoS) covers Non Functional requirements such as As microservices use disparate datasources like SQL store, NoSQL store, Cache, Object store like AWS S3, etc you need to map non functional requirements to…

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Security holes & how to fix them interview Q&A

Security is of paramount importance to any application or website. Applications with security vulnerabilities can not only tarnish the reputation of a company, but also can adversely impact the bottom-line of that organization. So, it really pays for the organizations to have the right people who can identity potential security…

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