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♦ 6 JSON interview Q&As

Q1. What is JSON and how does it differ from an XML? A1. JSON (JavaScript Object Notation) is a lightweight, text-based, language-netral like XML, but less verbose than XML data exchange format. JSON is used in Web services to exchange data between client and server. … Read more ›...

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001A: 7+ Java architectural patterns interview Q&As

One of the very frequently asked open-ended interview questions is – Can you describe the high-level architecture of the recent application you had worked on from 10,000 feet? ⏯ Java high-level architecture & Integration Styles

You will be asked to 1) draw a diagram on a white board and 2) follow up questions based on your answer.

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001B: Java architectural patterns interview Q&As

Continuation of Java architecture interview Q&A with integration styles & architecture diagrams – part 1 Q3. Can you discuss some of the high level architectures you are experienced with? A3. Be prepared for a white board session on architectures, especially the bird’s eye view of the last application you had...

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05: Q19- Q24 How to create a well designed Java application with OOP?

A software application is built by coupling various classes, modules, and components. Without coupling, you can’t build a software system. But, the software applications are always subject to changes and enhancements. So, you need to build your applications such a way that they can not only adapt to growing requirements,...

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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, … Read more ›...

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06: ♦ Q25 – Q32 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, … Read more ›...

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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) Q&As

Q1. What is an ERD? A1. ERD or Entity-Relationship Diagram, is a chart that visually represents the relationship between database entities. ERDs model an organization’s data storage requirements with three main components: entities, attributes, and relationships. As UML is for charting the relationships and interactions among Java entities like classes...

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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. … Read more ›...

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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. … Read more ›...

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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, CAP theorem defines: Consistency – Every read should give the most recent write. E.g. Consistency in SQL ACID property. Every node must be updated before allowing any further reads. … Read...

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18 Java scenarios based interview Q&As

Q1. Scenario: You need to load stock exchange security codes from a database and cache them for performance. The security codes need to be refreshed say every 30 minutes. This cached data needs to be populated and refreshed by a single writer thread and read by several reader threads. …...

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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 — … Read more ›...

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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. … Read more ›...

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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 Distributed systems interview Q&As

Q1. What are the key requirements to be a distributed system? A1. A distributed system must satisfy the following 3 characteristics. 1) The computers or nodes operate concurrently. 2) The computers or nodes fail independently, … Read more ›...

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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. …...

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7 Key Micro services Interview Questions Answered

Q1. How will you go about choosing REST vs Messaging for Micro Services? A1. Micro Services can be invoked both synchronously and asynchronously. Micro services must be organized around business functionalities like Customers, Orders, Invoices, Products, etc. Synchronous Request/Response & public facing APIs REST is a great fit for request/response...

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8 Java memory management interview Q&As

Q1. Are memory leaks possible in Java, which has memory management via automatic Garbage Collection? A1. Memory and resource leaks are possible in any robust application. In managed languages such as Java and C#, the developers do not have to worry too much about memory management as the garbage collector...

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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.

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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,

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QoS interview Q&As on Availability, Serviceability & Disaster Recoverability

Q1. What are the system qualities that typically form a basis for QoS requirements? A1. Quality of service (QoS) requirements are technical specifications that specify the system quality of features such as 1) Performance: Response times and throughput with respect to concurrent user load conditions. … Read more ›...

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Scalable Straight Through Processing System (OLTP) vs OLAP in Java

Large mission critical applications use Straight Through Processing, and these systems need to be highly scalable. So, when you apply for these high paying jobs, it really pays to prepare for your job interviews with the following questions and answers. Q. What is Straight Through Processing (STP)? … Read more...

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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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Top 6 tips to go about writing loosely coupled Java applications

6 tips to go about writing loosely coupled Java applications useful not only for talking the talk in Java job interviews, but also to build maintainable Java applications. Q1. What is tight coupling? A1. If class OrderServiceImpl relies on parts of class PaymentServiceImpl that are not part of interface PaymentService,...

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Why does good API design matter?

Q1. Why is a good API design important? A1. The Application Programming Interfaces (i.e. APIs) are fine grained services/libraries used by other applications, systems and libraries. A good API design improves flexibility, stability, and extendability of your application. Now a days, applications are built as reusable components or services. …...

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XML Processing Interview Q&A

Q1. What libraries can you use in Java to process XML documents? A1. #1. DOM Parser loads the whole XML structure into memory, and you can read and write. This is useful for smaller XML documents which don’t impact memory usage. … Read more ›...

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