DigiValet Senior Java Developer Interview Questions and Answers

Q1. What is the difference between abstract class and an interface in Java?
Ans. 
Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.
• Abstract class can have constructors, member variables, and methods, while interface cannot.

• A class can implement multiple interfaces but can only extend one abstract class.

• Abstract classes are used to define a common behavior among subclasses, while interfaces are used to define a contract for classes to impl...read more
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Q2. An abstract class can have method implements and abstract method, while an interface only contains abstract method (before Java 8) . Abstract classes support single inheritance, whereas interfaces support ...read more
Ans. 
Abstract classes can have both implemented and abstract methods, while interfaces can only have abstract methods. Abstract classes support single inheritance, interfaces support multiple inheritance.
• Abstract classes can have both implemented and abstract methods, providing more flexibility in design.

• Interfaces can only have abstract methods, promoting a more strict contract for implementing classes.

• Abstract classes sup...read more
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Q1. Number series in aptitude
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Number series in aptitude involves identifying the pattern in a sequence of numbers and predicting the next number.
• Look for patterns such as arithmetic progression, geometric progression, or a combination of both.

• Check for alternate numbers, differences between consecutive numbers, or multiplication factors.

• Consider prime numbers, squares, cubes, or other mathematical operations applied to the series.

• Example: 2, 4, 6, ...read more
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Q2. Relation ships in berbal
Ans. 
Relationships in verbal communication are crucial for effective collaboration and understanding.
• Verbal communication involves both verbal and non-verbal cues

• Active listening is key to building strong relationships in verbal communication

• Clarity and conciseness in speech can enhance relationships

• Empathy and understanding of others' perspectives are important in verbal relationships
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Q1. Explain the four branches of oops
Ans. 
The four branches of OOP are encapsulation, inheritance, polymorphism, and abstraction.
• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: The ability for objects of different classes to respond to the same method call.

• Abstraction: Hiding the complex implementation details and showing only
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Q2. Explain about the structures in c
Ans. 
Structures in C are user-defined data types that allow grouping of variables of different data types under a single name.
• Structures are used to represent a record which consists of different data types.

• They are defined using the 'struct' keyword.

• Each variable in a structure is called a member.

• Structures can be nested within other structures.

• Example: struct employee { int emp_id; char emp_name[50]; float emp_salary; };

• E
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The aptitude test evaluates problem-solving, coding skills, and logical reasoning, offering a fair challenge to showcase technical expertise.

Q1. How do you handle conflicts in a team project?
Ans. 
I address conflicts in team projects by promoting open communication, active listening, and seeking compromise.
• Encourage open communication among team members to address conflicts early on

• Practice active listening to understand all perspectives and concerns

• Seek compromise and find common ground to resolve conflicts effectively
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Q2. What is the difference between an interface and an abstract class?
Ans. 
Interface is a contract that defines the methods a class must implement, while an abstract class can have both implemented and abstract methods.
• Interface can only have abstract methods and cannot have any implementation, while abstract class can have both abstract and implemented methods.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Interfaces are used to achieve multiple inheri...read more
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Questions on string and arrays both are moderate level questions on hacherrank type for 20 marks

Q1. Constructor chaining
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Q2. Hasmap and treemap
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Q1. 3 Question was there related to architecture and Computer networks.
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Q1. Microservices and Monolith.
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Q2. Leetcode hard Sum.
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Aptitude questions with some basic coding questions

They have given 3 coding questions and some pseudo codings

Q1. Tell about your self
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Q2. Some coding questions
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Logical thinking and quantitative

One Java and one SQL and one js question

Q1. What is collections
Ans. 
Collections are data structures that store and organize multiple elements in a single unit.
• Collections provide methods to add, remove, and manipulate elements.

• Examples of collections include arrays, lists, sets, and maps.

• Collections can be used to efficiently manage and access large amounts of data.
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Q2. What is constructor
Ans. 
A constructor is a special method in a class that is automatically called when an object of that class is created.
• Constructors have the same name as the class they belong to

• They are used to initialize the object's state

• Constructors can have parameters to customize the initialization process
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Q3. What is data science
Ans. 
Data science is a field that uses scientific methods, algorithms, and systems to extract knowledge and insights from structured and unstructured data.
• Data science involves collecting, analyzing, and interpreting large amounts of data to make informed decisions.

• It combines statistics, machine learning, and domain knowledge to uncover patterns and trends in data.

• Data scientists use programming languages like Python and R...read more
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