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01: 12+ Git Source control must know basics interview Q&As

Q1. How does Git differ from SVN (i.e Subversion)? A1. #1. Git is a distributed source control system meaning that there will be multiple client repositories. SVN is one repository with lots of clients. GIT is decentralized to a point where people can track their own edits locally without having…

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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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01: 14 Unix must-know interview questions & answers

Q1 How do you remove the Control-M characters from a file?
A1 Control-M is a carriage return on keyboard. The ^M is the keyboard equivalent to \r. In a file originated from DOS/Windows the \r\n is used for an end of line carriage return, whereas in Unix it is \n for a new line.

So, if created a file in DOS/Windows and copied it to a Unix machine, you need to convert the carriage returns from \r\n to \n. You need to remove \r.

Using the sed command that replaces Control-M with nothing

Note: The ^M is typed on the command line with ctrl+v and ctrl+M

You can also use a vi editor and type :%s/^M//g to remove the control-M characters.

Q2 How will you search for a property named “inbox” within a number of .properties files including all sub folders?
A2 Using the find and grep commands. Yoo can use xargs command or -exec attribute. xargs is faster.

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01: 21 Docker DevOps interview Q&As

Docker, Jenkins, CI/CD, & DEV/OPS have been the buzz words for the last several years. You will be seeing this in more often in the job requirements as well. Docker Tutorial – compile & run Helloworld.java. Q1. What is a Docker container, and what does it enable you to do?…

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01: Can you design classes & interfaces using OO?

Q1. How would you go about designing a “farm animals” application where animals like cow, pig, horse, etc move from a barn to pasture, a stable to paddock, etc? The solution should also cater for extension into other types of animals like circus animals, wild animals, etc in the future….

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01: High level & low level system design considerations for read heavy systems

Q1. What are some of the design considerations for a read heavy system? A1. Before designing any systems, one should gather the functional & non-functional requirements. The SLAs (i.e. Service Level Agreements) have to be clearly defined. A rough-cut capacity planning has to be done in terms of how many…

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01: High level & low level system design considerations for write heavy systems

This extends High level & low level system design considerations for read heavy systems Q1. What are some of the design considerations for a write heavy system? A1. Before designing any systems, one should gather the functional & non-functional requirements. The SLAs (i.e. Service Level Agreements) have to be clearly…

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01: jvisualvm tutorial to sample Java heap memory

Java does not have a sizeof operator like C++ does. Java uses automatic memory management known as the Garbage Collection, hence it is not that important to evaluate size of various objects. But, for the purpose of learning & fixing any potential memory issues, I have used “jvisualvm”, which is…

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01: NoSQL interview Q&As – Key Value, Wide Column, Document & Graph databases

Q1. What are the key differences between SQL & NoSQL databases? A1. Now a days you have a choice which database to use based on your requirements. There are pros & cons for each database. SQL NoSQL (Not Only SQL) SQL databases store structured data & enforces schema (i.e. structure)…

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01: Q13 “12 Rules” for REST API design & development

These are more like rules to develop RESTFul web services as opposed to being the best practices. REST is an architectural style without any contracts or specifications. So, it is imperative to apply the following rules for better REST API design. #1. Write stateless RESTFul services This means each request…

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