Backend Developer

There are a number of benefits of web services. Some of the prominent benefits are: 

• Reusability – A single web service can be used by a number of client applications at the same time. 
• Interoperability – Web services can be accessed through the network. It uses XML/ JSON for transporting data and runs on HTTP/ Soap protocol. It can be easily developed using any programming language.  
• Easy to integrate and deploy – Integration and deployment of web services can be done much more easily and in less time. 
• Multiple service versions – A number of service versions can run at the same time.  
• Loose coupling – The client code of web services is independent of server code. So, the loose coupling can be achieved in the application.  

This is one of the common backend developer interview questions that you are likely to come across in the interviews. It tests the fundamental knowledge of the candidates. Performance testing is the testing technique that evaluates the responsiveness, scalability, stability, and speed of the applications. It tests how well an application can perform under different load conditions. The different steps involved in performance testing are: 

• Identification of the testing environment 
• Identification of performance metrics 
• Planning and designing of performance tests 
• Configuration of test environments 
• Implementation of the test design 
• Execution of the tests 
• Analysis and reporting of the test results. 

Expect to come across this popular question in junior backend developer interview questions.

In order to ensure better outcomes of performance testing, it is vital to have knowledge of the best practices. Some of the best practices of performance testing are: 

• Conduct the performance test as early as possible during the development stage 
• Test the software units separately first and then test the units together 
• Baseline measurements should be the starting point of performance testing
• Conduct a number of performance tests in order to ensure consistent findings 
• Keep the test environment of performance tests consistent 
• Isolate the environment of performance testing from the environment suitable for the quality assurance testing 
• Calculate averages in order to get actionable metrics.

Software architecture is all about creating the structure of the program. In order words, it is referred to as the bare skeleton of the software program. On the other hand, software design involves the process of implementing codes to meet the software requirements. Software architecture is the blueprint of the program, while software design is the process of building the program. Both software design and software architecture are two different processes that work together to form an integrated development process.

Scalability is considered to be an important aspect of ensuring improved productivity of software programs. It is mainly related to high user demands. It ensures that the software program is able to adapt different functions well when the amount of user data increases. Checking the scalability helps in determining the lifetime validity of the software programs. If a software program is not scalable, it will not be able to function properly with the increase in audience. In case of a lack of scalability, there is a need to rewrite the application to ensure that it adapts well to the growth in audience. The features such as API, states, cache, etc., can help in increasing the scalability of the software programs.

When there is no live code testing, interviewers usually ask such questions in order to gain insights into your practical knowledge about backend development. There does not exist any concept such as perfect code. Debugging is important to identify potential flaws in a software program. It is the process of identifying the bugs and fixing them at the right time to ensure the optimum performance of the application. While answering this question, you will have to name a few debugging tools that you use to fix the issues in the applications. You also need to mention the different steps for fixing the potential issues. Remember, different bugs are handled in different manners. So, you need to answer this question accordingly.

A clustered index involves storing the rows physically on the disk in the same order as they appear on the index. Therefore, there can be only one clustered index. The clustered index mainly tells the database to store values present next to one another on the disk. On the other hand, a non-clustered index consists of a second list with pointers to the different physical rows. Unlike a clustered index, there can be a number of non-clustered index. With the increase in new indexes, the time required for writing new records also increases.

In Java, an immutable class refers to a class that cannot be modified after its creation. Some of the ways of creating an immutable class are: 

• Declare the class as final to avoid the creation of child classes. 
• Declare the data members present in the class as final to ensure that the values do not change after the creation of the objects. 
• Declare the data members present in the class as private in order to prevent direct access.
• Perform a deep copy of different objects to return a copy and not the real object reference. 

Thread can be defined as the individual path of execution through the program codes. Threads are mainly used to increase the speed of Java applications and enhance their overall responsiveness by doing a number of things simultaneously. There are different kinds of threads used. The two prominent kinds of threads are user threads and daemon threads. User threads refer to high-priority threads. On the other hand, the daemon threads are the low-priority threads whose role is to deliver services to different user threads.

Microservices architecture refers to the integration of a number of small but independently deployable services into a single application. It helps in increasing the versatility of operations as various programming languages are used in order to write individual services. So, one can use different languages for different services. There are a number of benefits to choosing microservices architecture. One of the most significant benefits is that it can adapt to new technologies and frameworks. Moreover, the failure of one process will not affect the functioning or operations of the entire system. Another significant benefit of microservices architecture is that it can get up and running in a very short period of time.

A common question in interview questions backend developer, don't miss this one.

ACID is the short form that is used in order to define different properties of a relational database system. ACID refers to 4 separate terms. It includes: 

• Atomicity – It refers to the property that states if one part of the transaction fails, then the whole transaction will fail. However, the database state remains unchanged. 
• Consistency – It is the property that ensures performing any transaction will move the database from one state to another. 
• Isolation – As per this property, in case two transactions are performed simultaneously, it will result in a state that would have been obtained when transactions were carried out in a sequential manner.
• Durable – The property indicates the completion of a transaction. The properties and shape of the transactions will not change even if the power goes off.

Containerization refers to the visualization strategy that is an ideal alternative to traditional hypervisor-based virtualization. Containerization involves the sharing of the operating system by a number of containers instead of being cloned for individual virtual machines.

The complexity of data is increasing a lot in recent times. NoSQL can help in resolving the issue. It can be defined as a mechanism that is used for the retrieval and storage of data. It is a type of database that can effectively handle and sort messy, complicated, and unstructured data. It can be considered as thinking in a new way about databases. There are several types of NoSQL databases. Some of the significant types include key-value, graph, document-oriented, and column-oriented.

Many developers prefer using Go programming owing to the various benefits it offers. Some of the main benefits of Go programming are: 

• Its simplicity and conciseness make it ideal for use. 
• It provides quality support for type embedding and interfaces. 
• The compilation timing of Go programming is quite fast in comparison to other programming. 
• It provides support for different environments adopting patterns that are similar to dynamic languages. 
• Go programming comes with in-built concurrency support. 

Availability can be defined as the ability of the users of an application to access the systems. In case a user is not able to access the system, it is considered to be unavailable. High availability indicates that an application will be available to the user without interruption. To achieve high availability in the case of web applications, redundant server nodes can be used along with clustering. Availability is expressed in the form of a percentage of uptime in a given year.

Availability can be defined as the ability of the users of an application to access the systems. In case a user is not able to access the system, it is considered to be unavailable. High availability indicates that an application will be available to the user without interruption. To achieve high availability in the case of web applications, redundant server nodes can be used along with clustering. Availability is expressed in the form of a percentage of uptime in a given year.

A reverse proxy can be defined as a type of proxy that can retrieve data from a number of services on behalf of clients. It returns data to the clients in such a way that it seems that data actually originated from the reverse proxy server. The reverse proxy is mainly used in order to balance the load.

Continuous delivery refers to the process of continuous integration to ensure the quick release of different changes to the customers. Apart from the automation of the testing process, the process of starting and releasing the program can also be automated.  

On the other hand, continuous integration allows the developers to merge the changes to the main branch. It helps eliminate the chaos and ensures the faster release of the software products.

Continuous deployment allows each of the shifts going through the production stages to quickly reach out to the customers.

The full form of BASE is Basically Available, Software state, Eventual consistency. The BASE properties refer to the general properties that are inherent in the NoSQL systems. It does not provide any guarantee of consistency. However, it provides a guarantee of availability. The soft structure of the system suggests that the state of the system is likely to change over time.

Mocks refer to the objects with preprogrammed expectations shaping the specifics of the call. On the other hand, stubs can be defined as the standard responses to calls that are made during the test. Stubs are capable of recording call information. For instance, the email gateway stub is capable of remembering the message it has sent. Fake objects have various working implementations. However, they will require a reduction, thereby making them unusable for production.

This is one of the common junior backend developer interview questions that you are likely to come across. Spike testing refers to a type of stress testing that involves the evaluation of the performance of software when there is a rapid increase in the workload. For a short period of time, the load is likely to exceed the expectations.

The CAP theorem was published by Eric Brewer. According to the theorem, a distributed computer system cannot simultaneously guarantee consistency, availability, and partition tolerance. Consistency is the attribute that ensures all the nodes show the same data at the same time. Availability is the guarantee that ensures all the requests will receive a response as to whether it has failed or were successful. Partition tolerance ensures that the system continues its operation despite the loss or failure of the arbitrary message. A number of top companies, such as Google, Facebook, and Amazon, use this theorem in order to decide on their application architecture.