100+ Senior Developer Interview Questions and Answers

To handle hashmap memory leak, ensure proper management of keys and values, use weak references, and periodically check for unused entries.

• Avoid storing unnecessary data in the hashmap

• Use weak references for keys or values if appropriate

• Periodically check for and remove unused entries to free up memory

Implementing system design scenarios for monitoring and alarming

• Utilize monitoring tools like Prometheus, Grafana, or Nagios to collect and visualize data

• Set up alerts based on predefined thresholds for key metrics

• Implement a centralized logging system like ELK stack to track system behavior

• Utilize distributed tracing tools like Jaeger or Zipkin to monitor request flows

• Implement health checks for services to ensure they are running properly

Implement security in Azure APIM by using policies, OAuth 2.0, and API keys.

• Use policies in Azure APIM to enforce security measures such as rate limiting, IP filtering, and JWT validation.

• Implement OAuth 2.0 authentication to secure APIs and control access to resources.

• Generate and manage API keys to authenticate and authorize clients accessing the APIs.

• Utilize Azure Active Directory for identity management and user authentication.

• Encrypt sensitive data in transit and at rest...read more

Load balancing in Azure involves distributing incoming network traffic across multiple servers to ensure optimal resource utilization and prevent overload.

• Use Azure Load Balancer to distribute incoming traffic across multiple VM instances within a virtual network

• Configure load balancing rules to define how traffic is distributed based on criteria such as port number or protocol

• Utilize Azure Traffic Manager for global load balancing across multiple Azure regions or data center...read more

The .NET framework has major components like Common Language Runtime, Class Library, ASP.NET, ADO.NET, and Windows Forms.

• Common Language Runtime (CLR) - manages memory, security, and execution of code

• Class Library - reusable code for common functionality

• ASP.NET - web application development framework

• ADO.NET - data access technology

• Windows Forms - desktop application development framework

Custom settings are org-specific, while custom metadata can be deployed across orgs.

• Custom settings are hierarchical and can be accessed using a hierarchy custom setting type

• Custom metadata is deployable and can be used in managed packages

• Custom settings are stored in the application cache, while custom metadata is stored in the metadata cache

Using sliding window technique to find subarray with sum equal to k.

• Initialize two pointers at the start of the array.

• Move the right pointer to expand the window until the sum is greater than or equal to k.

• Move the left pointer to shrink the window if the sum exceeds k.

• Repeat until the end of the array is reached.

• Example: Input array [1, 4, 20, 3, 10, 5], k=33. Output: [20, 3, 10].

JDK is a development kit, JRE is a runtime environment, and JVM is a virtual machine. Equals compares object values, HashCode returns a unique integer for an object.

• JDK includes JRE and development tools, while JRE includes JVM and necessary libraries

• JVM is responsible for executing Java bytecode

• Equals method compares the values of two objects, while == compares their references

• HashCode method returns a unique integer for an object, used for hashing and storing objects in col...read more

Yes, I have experience developing applications independently.

• I have successfully developed multiple applications on my own in the past.

• I am proficient in various programming languages and technologies required for application development.

• I am capable of handling the entire development process from design to deployment.

• I have strong problem-solving skills to troubleshoot and resolve issues independently.

Mulesoft is an integration platform that connects applications, data, and devices.

• Mulesoft is used for building APIs and integrating different systems

• It provides a unified platform for managing APIs, integrations, and analytics

• Mulesoft uses Anypoint Studio for development and deployment

• It supports various protocols and data formats including REST, SOAP, JSON, and XML

• Mulesoft offers pre-built connectors for popular applications and services such as Salesforce, SAP, and AWS

Web API uses attribute routing and convention-based routing for routing mechanism.

• Web API uses attribute routing to define routes directly on the controller actions or at the controller level.

• Convention-based routing is based on the naming conventions of the controller and action methods.

• Attribute routing allows for more control over the URIs and is preferred for complex routing scenarios.

Default methods in Java 8 allow interfaces to have method implementations.

• Default methods were introduced in Java 8 to allow interfaces to have method implementations.

• They provide a way to add new methods to interfaces without breaking existing implementations.

• Default methods are defined using the 'default' keyword in the interface.

• They can be overridden in implementing classes if needed.

• Example: interface MyInterface { default void myMethod() { System.out.println('Default me...read more

The Pharma industry is involved in the research, development, production, and marketing of pharmaceutical drugs.

• Pharma industry focuses on developing and producing medications for various health conditions.

• It involves extensive research and clinical trials to ensure the safety and efficacy of drugs.

• Pharmaceutical companies market their products to healthcare professionals and consumers.

• Regulatory bodies such as the FDA oversee the approval and monitoring of pharmaceutical pro...read more

A string is a sequence of characters used to represent text in programming.

• Strings are commonly used for storing and manipulating text data in programming languages.

• Strings are typically enclosed in quotation marks, such as 'hello world'.

• String manipulation functions can be used to modify and extract information from strings.

Kafka is a distributed streaming platform, Partition is a way to divide data, ConsumerGroup is a group of consumers sharing the load.

• Kafka is a distributed streaming platform used for building real-time data pipelines and streaming applications.

• Partition is a way to divide data within a Kafka topic to allow for parallel processing and scalability.

• ConsumerGroup is a group of consumers that work together to consume data from Kafka topics, each consumer within the group reads fr...read more

Use React state to toggle between dark and light mode in a web app

• Create a state variable to track the current mode (dark or light)

• Use CSS classes to style the app differently based on the current mode

• Implement a button or toggle switch to allow users to switch between modes

Prototypes in JavaScript are used for inheritance and allow objects to inherit properties and methods from other objects.

• Prototypes are used to add new properties or methods to all instances of an object.

• They are used to share methods across multiple objects.

• Prototypes are accessed using the prototype property of a constructor function.

• Example: function Person(name) { this.name = name; } Person.prototype.greet = function() { return 'Hello, my name is ' + this.name; };

I have 8 years of experience in C, Python, and Oracle.

• 8 years of experience in C programming, including developing applications and optimizing code.

• Proficient in Python for scripting, automation, and web development.

• Extensive experience in Oracle database management, including SQL queries and performance tuning.

Strings are stored as arrays of characters in memory.

• Each character is assigned a unique numerical code according to the character encoding used.

• Strings are immutable in most programming languages, meaning they cannot be changed once created.

• String manipulation functions create new strings rather than modifying the original.

• Strings can be concatenated using the + operator or string interpolation.

• Examples of character encodings include ASCII, Unicode, and UTF-8.

Batch job is a process of executing a series of jobs in a batch mode. Scatter gather is a technique of parallel processing.

• Batch job is used for processing large volumes of data in a batch mode.

• Scatter gather is used for parallel processing of data across multiple nodes.

• Batch job is sequential in nature while scatter gather is parallel.

• Batch job is commonly used in ETL processes while scatter gather is used in distributed computing.

• Example of batch job is processing payroll f...read more

Iterate through a tree structure and find the shortest path

• Use a depth-first or breadth-first search algorithm to traverse the tree

• Keep track of the current path while traversing

• Compare the length of each path to find the shortest one

• Consider using a priority queue or a min-heap to optimize the search

Yes, we have used the Factory Method and Singleton design patterns in the current project.

• Factory Method pattern was used to create objects without specifying the exact class of object that will be created.

• Singleton pattern was used to ensure a class has only one instance and provide a global point of access to it.

CRUD operations code for Senior Developer interview

• Create - INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...)

• Read - SELECT column1, column2, ... FROM table_name WHERE condition

• Update - UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition

• Delete - DELETE FROM table_name WHERE condition

Hashmap and Hashtable are both used to store key-value pairs, but Hashtable is synchronized and slower than Hashmap.

• Hashmap is not synchronized and allows null keys/values.

• Hashtable is synchronized and does not allow null keys/values.

• Hashmap is faster than Hashtable.

• Hashmap is preferred for non-threaded applications.

• Hashtable is preferred for threaded applications.

• Example: HashMap map = new HashMap<>();

• Example: Hashtable table = new Hashtable<>();

SSL in ACE is configured using SSL profiles which define the SSL settings for a virtual server.

• SSL profiles in ACE define the SSL version, cipher suite, key exchange algorithm, etc.

• SSL profiles can be attached to a virtual server to enable SSL encryption for client connections.

• ACE supports SSL termination where SSL connections from clients are decrypted at the ACE and forwarded to backend servers in clear text.

Using Java 8, reverse an array of strings

• Use Arrays.stream() to convert the array to a stream

• Use Collections.reverse() to reverse the stream

• Use Collectors.toList() to convert the stream back to a list

Implementation of list in Scala

• Use the List class in Scala to create a list

• Lists are immutable and can hold elements of the same type

• Example: val myList = List(1, 2, 3, 4, 5)

Yes, @Transactional uses AOP internally.

• Transactional annotation is implemented using Spring AOP.

• AOP intercepts the method calls and applies transactional behavior.

• AOP proxies are created for the transactional methods.

• AOP uses dynamic proxies or CGLIB proxies to create the proxies.

Validate if a binary tree is valid or not

• A valid binary tree should not have any duplicate nodes

• A valid binary tree should have all left nodes smaller than the parent node and all right nodes greater than the parent node

• We can use recursion to traverse the tree and check if it is valid

Hashmap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• Hashmap uses an array to store the key-value pairs

• The key is hashed to find the index in the array where the value is stored

• If two keys hash to the same index, a linked list is used to store multiple values

• Hashmap uses load factor to determine when to resize the array

• Hashmap provides constant time complexity for insertion, deletion, and retrieval

A closure is a function that has access to its own scope, as well as the outer scope in which it was defined.

• A closure can access variables from its outer function even after the outer function has finished executing.

• Closures are commonly used in event handlers, callbacks, and asynchronous code.

• Example: const outerFunction = () => { const outerVar = 'I am outer'; return () => { console.log(outerVar); }; }; const innerFunction = outerFunction(); innerFunction(); // Output: 'I ...read more

JavaScript is single-threaded, but can achieve multi-threading through Web Workers.

• JavaScript is inherently single-threaded, meaning it can only execute one set of instructions at a time.

• Web Workers allow JavaScript to create separate threads for parallel processing.

• Web Workers run in the background and do not block the main thread, enabling multi-threading in JavaScript.

• Example: Creating a new Web Worker using the Worker constructor and passing a script file to execute.

Caching is the process of storing frequently accessed data in a temporary storage area for faster access.

• Caching reduces the time it takes to access data by storing it closer to the user or application.

• It can be implemented at various levels such as browser, server, database, etc.

• Examples include browser caching of web pages, server caching of API responses, and database caching of query results.

String pool is a memory area in Java where strings are stored to optimize memory usage. OOPS stands for Object-Oriented Programming System. HashMap is a data structure in Java that stores key-value pairs.

• String pool in Java is a special memory area where strings are stored to optimize memory usage.

• OOPS stands for Object-Oriented Programming System, a programming paradigm based on the concept of objects.

• HashMap is a data structure in Java that stores key-value pairs and uses h...read more

A defect is an error or flaw in a software application that causes it to behave unexpectedly or not as intended.

• Defects can be caused by coding errors, design flaws, or environmental factors.

• Defects can lead to system crashes, data corruption, or security vulnerabilities.

• Examples of defects include syntax errors, logic errors, and performance issues.

• Defects can be identified through testing, debugging, and code reviews.

IBM API Connect is a comprehensive API management solution that enables organizations to create, secure, manage, and socialize APIs.

• IBM API Connect allows developers to easily create APIs and expose them to internal or external consumers.

• It provides tools for API creation, testing, security, monitoring, and analytics.

• IBM API Connect also includes a developer portal for API documentation and collaboration.

• It supports various protocols and standards such as REST, SOAP, and OAut...read more

Check for loop in a linked list

• Use two pointers, one moving one node at a time and the other moving two nodes at a time

• If there is a loop, the two pointers will eventually meet

• If one of the pointers reaches the end of the list, there is no loop

The ETL process involves extracting data from a source, transforming it to fit the target system, and loading it into the destination.

• Extract data from source system

• Transform data to fit target system

• Load transformed data into destination system

Display property is used to define the type of box used for an HTML element.

• It specifies how an element should be displayed on the web page.

• It can be set to values like block, inline, inline-block, none, etc.

• It affects the layout and positioning of the element.

• It can also be used to control the visibility and accessibility of an element.

• Example: display: block; will make the element a block-level box.

Strong consistency ensures that all replicas of data are updated synchronously, while eventual consistency allows for temporary inconsistencies.

• Strong consistency guarantees that all clients see the same data at the same time.

• Eventual consistency allows for temporary inconsistencies but eventually all replicas will converge to the same state.

• Strong consistency is often used in systems where data integrity is critical, such as financial transactions.

• Eventual consistency is com...read more

SOLID is a set of principles for object-oriented programming to make software more maintainable, scalable, and robust.

• S - Single Responsibility Principle

• O - Open-Closed Principle

• L - Liskov Substitution Principle

• I - Interface Segregation Principle

• D - Dependency Inversion Principle

Reverse a string using recursion in Java

• Create a recursive method that takes a string as input

• Base case: if the string is empty or has only one character, return the string

• Recursive case: return the last character of the string concatenated with the result of calling the method with the substring excluding the last character

Step functions are a type of serverless function that allow you to create workflows by chaining multiple functions together.

• Step functions are used to coordinate multiple AWS services into serverless workflows.

• They allow you to define a series of steps in a workflow, with each step being a separate function.

• You can use step functions to handle complex business logic, long-running processes, and error handling.

• Step functions can be triggered by events or API calls.

• Example: A s...read more

Delegates are used to achieve loose coupling and separation of concerns in software development.

• Delegates allow methods to be passed as parameters to other methods.

• They enable event-driven programming.

• They facilitate the implementation of the observer pattern.

• They enable the creation of anonymous methods.

• They allow for the implementation of callback functions.

• They enable the creation of extensible and modular code.

• They allow for the implementation of inversion of control and ...read more

To add a node into a linked list, you need to update the pointers of the previous node and the new node.

• Create a new node with the data to be added

• Update the next pointer of the new node to point to the current node's next

• Update the next pointer of the current node to point to the new node

Binary search program code in Python

• Define a function that takes a sorted array and a target value as input

• Initialize two pointers, low and high, to the start and end of the array

• While low is less than or equal to high, calculate mid as (low + high) // 2 and compare array[mid] with target

• If array[mid] is equal to target, return mid

• If array[mid] is less than target, update low to mid + 1

• If array[mid] is greater than target, update high to mid - 1

• If target is not found, return ...read more

Calculating the size of a file system

• Determine the total size of all files and directories within the file system

• Include the size of all subdirectories and their contents

• Consider the size of metadata and file system overhead

• Use appropriate tools or commands to gather the necessary information