Future Focus Infotech Java Technical Lead Interview Questions and Answers

Q1. What are java 8 new features
Ans. 
Java 8 introduced lambda expressions, streams, default methods, and more.
• Lambda expressions for functional programming

• Streams for efficient processing of large data sets

• Default methods to add new functionality to existing interfaces

• Date and Time API for improved handling of date and time

• Optional class to avoid null pointer exceptions

• Nashorn JavaScript engine for improved performance

• Parallel array sorting for faster sor
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Q2. What is the difference between stream and parallel stream
Ans. 
Stream is sequential while parallel stream is concurrent
• Stream is a sequence of elements that can be processed sequentially

• Parallel stream is a sequence of elements that can be processed concurrently

• Parallel stream can improve performance for large datasets

• Parallel stream uses multiple threads to process elements in parallel

• Stream is suitable for small datasets or when order of processing is important
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Q1. Spring Security Implementation
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Q2. Api design Implementation
Ans. 
API design implementation involves creating a well-structured and user-friendly interface for interacting with software applications.
• Understand the requirements and use cases for the API

• Design clear and consistent endpoints with proper documentation

• Implement secure authentication and authorization mechanisms

• Follow RESTful principles for creating APIs

• Consider scalability and performance optimizations
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Q3. Stream API coding question
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Q1. I have added the questions below
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Q2. I have added thebelow
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Q1. == operation & .equals() method method overloading
Ans. 
The == operator is used to compare references in Java, while the .equals() method is used to compare values. Method overloading is when multiple methods have the same name but different parameters.
• Use == to compare references, use .equals() to compare values

• Method overloading allows multiple methods with the same name but different parameters

• Example: String str1 = new String("hello"); String str2 = new String("hello");...read more
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Q2. Linked list working with example
Ans. 
A linked list is a data structure where each element points to the next element in the list.
• Linked list is made up of nodes, each containing data and a reference to the next node.

• Insertion and deletion are efficient in linked lists compared to arrays.

• Example: Node 1 -> Node 2 -> Node 3 -> null
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Q1. Based on the resume
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Q1. Scenario based questions
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Q1. Package discussion
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Q1. Explain OOPs concepts.
Ans. 
OOPs concepts are fundamental principles of object-oriented programming that help in designing and implementing software solutions.
• Encapsulation: Bundling data and methods together in a class.

• Inheritance: Creating new classes by inheriting properties and behaviors from existing classes.

• Polymorphism: Ability of an object to take on many forms.

• Abstraction: Hiding complex implementation details and providing a simplified ...read more
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Q2. Write a program to count occurance the letter in a string.
Ans. 
This program counts the occurrence of each letter in a given string.
• Use a HashMap to store the count of each letter.

• Iterate through the characters of the string and update the count in the HashMap.

• Finally, print the count of each letter.
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Q3. Write a SQL query to find third highest salary from employee table.
Ans. 
SQL query to find third highest salary from employee table.
• Use the ORDER BY clause to sort the salaries in descending order

• Use the LIMIT clause to limit the result to the third row

• Use a subquery to exclude the highest and second highest salaries
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Q4. Difference between Array and arraylist.
Ans. 
Array is a fixed-size data structure while ArrayList is a dynamic-size data structure in Java.
• Array has a fixed length, while ArrayList can grow dynamically.

• Array can store both primitive types and objects, while ArrayList can only store objects.

• Array uses square brackets [] for declaration, while ArrayList uses angle brackets <>.

• Array provides direct access to elements using index, while ArrayList provides methods for...read more
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Q5. Explain working of Arraylist.
Ans. 
ArrayList is a dynamic array that can grow or shrink in size. It stores objects and provides methods for adding, removing, and accessing elements.
• ArrayList is part of the Java Collections Framework.

• It is implemented as a resizable array.

• Elements can be added using the add() method.

• Elements can be accessed using the get() method.

• Elements can be removed using the remove() method.

• The size() method returns the number of el...read more
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Q6. What is the default size of an arraylist.
Ans. 
The default size of an ArrayList is 10.
• The default initial capacity of an ArrayList is 10.

• If the number of elements exceeds the initial capacity, the ArrayList automatically increases its size.

• The capacity of an ArrayList can be increased manually using the ensureCapacity() method.
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Q7. Some questions from my resume about my previous experience.
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Q8. The interviewer was stupid and in my opinion they are just wasting your precious time. After the interview they don't provide any updates about the interview.
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Collection , logical

Q1. Opps ,spring boot
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Q2. Explain opps concept, what is spring boot
Ans. 
OOPs concept is a programming paradigm based on the concept of objects, Spring Boot is a framework for building Java applications.
• OOPs concept stands for Object-Oriented Programming, which focuses on creating objects that interact with each other to solve problems.

• It involves concepts like inheritance, encapsulation, polymorphism, and abstraction.

• Spring Boot is a framework that simplifies the development of Java applic...read more
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Q3. What is controller and rest controller
Ans. 
Controller is a class that handles user requests and returns appropriate response. Rest controller is a specialized controller for RESTful web services.
• Controller is a class in MVC architecture that handles user requests and interacts with the model and view.

• Rest controller is a specialized controller in Spring framework for building RESTful web services.

• Rest controller uses annotations like @RestController and @Reques...read more
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Q4. Internal working of hashmap
Ans. 
HashMap is a data structure that stores key-value pairs and uses hashing to efficiently retrieve values.
• HashMap internally uses an array of linked lists to store key-value pairs.

• When a key-value pair is added, the key is hashed to find the index in the array where it will be stored.

• If multiple keys hash to the same index, a linked list is used to handle collisions.

• HashMap allows null keys and values, but only one null ...read more
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Q5. Who is best jdbc or hibernate
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Theory plus coding questions

Q1. Core Java , spring boot questions, project
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Q2. Project challenges how resolved
Ans. 
Resolved project challenges through effective problem-solving techniques.
• Identified the root cause of the challenges

• Collaborated with team members to brainstorm solutions

• Implemented appropriate strategies to overcome obstacles

• Tested and validated the implemented solutions

• Documented the resolution process for future reference
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Q3. Difficult situation in project while working with team how resolved
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Q4. Core string concept in depth
Ans. 
Core string concepts include immutability, string manipulation, and string comparison.
• Strings in Java are immutable, meaning they cannot be changed once created.

• String manipulation can be done using various methods like concatenation, substring, and replace.

• String comparison can be done using equals() method for content comparison and == operator for reference comparison.
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Q5. Soft skills questions
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