TCS iON Java Developer Interview Questions, Process, and Tips

Q1. What is a wrapper class in java
Ans. 
Wrapper classes in Java are classes that allow primitive data types to be accessed as objects.
• Wrapper classes provide a way to convert primitive data types into objects.

• They are used when an object is required, such as in collections or generics.

• Examples include Integer for int, Double for double, Boolean for boolean, etc.
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Q2. Encapsulation with an example?
Ans. 
Encapsulation is the concept of bundling data and methods that operate on the data into a single unit.
• Encapsulation helps in hiding the internal state of an object and restricting access to it.

• It allows for better control over the data by preventing external code from directly modifying it.

• Example: A class 'Car' with private variables like 'model', 'year', and public methods like 'getYear()' and 'setModel()'.
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Q3. What is the difference between hashmap and hashset
Ans. 
HashMap is a key-value pair collection while HashSet is a collection of unique elements.
• HashMap stores key-value pairs while HashSet stores unique elements.

• HashMap allows duplicate values but keys must be unique, while HashSet does not allow duplicates.

• HashMap uses keys to retrieve values, while HashSet does not have keys and values are the same.

• Example: HashMap map = new HashMap<>(); HashSet set = new
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Q4. What is the usage of optinal class
Ans. 
Optional class is used to handle null values in Java, preventing NullPointerExceptions.
• Optional class was introduced in Java 8 to provide a more elegant way of handling null values.

• It encourages developers to explicitly handle the presence or absence of a value, rather than relying on null checks.

• Optional class has methods like isPresent(), get(), orElse(), etc. to work with optional values.

• Using Optional class can mak...read more
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Q1. Just basic question tell me about yourself
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Reasoning and quants

Coding test questions

Group discussion practice

Case study practice

Q1. Any type questions
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Q1. Easy questions given
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Q1. Opps concepts hibernate
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Q2. Comparator comparable , spring boot
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Mathematical and logical questions

Based on coding and programming

Q1. Oops concept in java
Ans. 
Oops concept in java
• Object-oriented programming paradigm

• Encapsulation, Inheritance, Polymorphism, Abstraction

• Classes and Objects

• Access Modifiers

• Interfaces and Abstract Classes
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Q2. Oops concept in c++ programming language
Ans. 
OOPs concepts in C++ include inheritance, polymorphism, encapsulation, and abstraction.
• Inheritance allows a class to inherit properties and methods from another class.

• Polymorphism allows objects to take on multiple forms.

• Encapsulation hides the implementation details of a class from other objects.

• Abstraction focuses on the essential features of an object and hides the unnecessary details.

• Example: A car class can inheri...read more
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Q1. What was your hobbies
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Q2. Tell about yourself??
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Q3. What role ur in interested in??
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Q1. About your experience
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Q2. About your biggest strength
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Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions on Core Java concepts.

Q1. What are the primitive data types in Java?
Ans. 
byte: The byte data type is an 8-bit signed two's complement integer. It has a minimum value of -128 and a maximum value of 127 (inclusive). The byte data type can be useful for saving memory in large arrays, where the memory savings actually matters.

short: The short data type is a 16-bit signed two's complement integer. It has a minimum value of -32,768 and a maximum value of 32,767 (inclusive). 

int: By default, ...read more
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Q2. What is the JVM?
Ans. 
It is :
A specification where working of Java Virtual Machine is specified. But implementation provider is independent to choose the algorithm. Its implementation has been provided by Oracle and other companies.
An implementation Its implementation is known as JRE (Java Runtime Environment).
Runtime Instance Whenever you write java command on the command prompt to run the java class, an instance of JVM is created.
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Q3. Why is Java considered an object-oriented language?
Ans. 
Java is object oriented programming language because without class and object it is impossible to write any Java program.
Java is not pure object oriented programming language because java has predefined primitive data types (which are not objects) and you can access the members of a static class without creating an object of it.
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Q4. What is JIT in Java?
Ans. 
Just-in-time, or JIT, is an inventory management method in which goods are received from suppliers only as they are needed. The main objective of this method is to reduce inventory holding costs and increase inventory turnover. Just in time requires carefully planning the entire supply chain and usage of superior software in order to carry out the entire process till delivery, which increases efficiency and eliminates ...read more
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