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01: 13 Java low latency interview questions & answers

Have you seen job advertisements requiring Java candidates to work in low latency, high throughput, real-time and distributed systems with share-nothing architectures? Wondering what questions you will be asked? If you are an experienced Java developer targeting high paying skills then it pays to get a good handle on Java low latency interview questions & answers.

You will be quizzed on the low latency application you had recently worked on especially the outcomes in terms of the latencies, response times, and throughput along with the challenges you faced.

Q1. What do you understand by the term latency?
A1. Latency is the time required to perform some action or to produce some result. Latency is measured in units of time like seconds, milli seconds, micro seconds, nanoseconds, etc.

What defines a “low” latency depends on the context

Low latency over the internet might be 200ms whereas low latency in a trading application (e.g. pricing or order matching engines) using FIX (i.e. Financial Information eXchange ) or proprietary protocols over TCP/IP might be 50µs to 100µs.

Q2. What do you understand by the term throughput?
A2. Throughput is the number of such actions executed or results produced per unit of time. This is measured in units of time like requests per second. The term “memory bandwidth” is sometimes used to specify the throughput of memory systems.… Read more ...

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02: 15 key considerations for low latency Java applications

Extends Writing low latency applications in Java interview Q&As. If the job description says “low latency” application, then be prepared. Even if “low latency” experience is not a requirement, all employers like candidates who can not only build systems that perform well, but also can stress test (e.g. JMeter), profile…

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02: 5 Java multithreading scenarios interview Questions & Answers

Java interview questions & answers on multithreading scenarios to judge your experience in building applications with concurrency in mind. Q1. Can you give some scenarios where you built concurrent systems? A1. In a concurrent system different threads run concurrently, whereas in a distributed system different processes often in separate machines…

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03: Networking basics interview Q&As on VPN, Proxy Server & Reverse Proxy

This post extends the 01: Networking basics interview Q&As on ip address, subnet mask, DNS & gateway with some of the key networking concepts that we face as software engineers & architects. VPN Q1. What is a VPN? A1. VPN stands for Virtual Private Network. In other words VPN is…

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

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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1. Asynchronous processing in Java real life examples – part-1

The scenario based questions are very popular with the job interviewers, and some scenario based questions are related to decoupling and asynchronous (aka non-blocking) processing in Java with message queues/topics, database tables where one process inserts data and another process consumes the inserted data, and Future objects in Java multi-threading….

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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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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: 5 Java synchronize & concurrency mgmt scenarios interview Q&As

This extends Q1. Can you give some scenarios where you had used multi-threading in Java applications? Q2. Can you give some scenarios where you used the synchronized keyword in Java? A2. Firstly, you need to assume that your code is always going to be accessed by multiple threads. Scenario 1:…

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15+ slacknesses or lack of experience that can come back & bite you as an architect, experienced programmer or data engineer

Production issues seek the attention of middle and top level management. Often these are intermittent issues that are harder to reproduce in lower environments without the right know-hows & tools. Some will shrug it off as “Cannot be reproduced“, whilst others will seize the opportunity to showcase their technical strengths & know hows to go places. Here are a few things that you must pay attention as a software developer, designer or architect to prevent any future embarrassments. You can use this as a check list.

#1: Not externalizing configuration values in config file(s) (E.g: .properties, .xml, or .yaml). For example, not making the number of threads used in a batch job configurable via a config file. You may have a batch job that worked well in DEV environment, but when deployed to PROD it takes a longer time to complete due to larger datasets. If the number of threads are configurable, the number of threads can be tweaked. This applies to all other configurable values like web service URLs, host names, port numbers, log levels, timeout values, etc. A Config Server is a MicroServices Architecture (aka MSA) feature where all configurable parameters of Microservices are written to & maintained.

#2: Not testing the application with the right volume of data. For example, testing your application with 1 to 3 accounts instead of 1000 to 2000 accounts, which is the typical scenario in the production environment.… Read more ...



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