TCS Java Developer Interview Questions, Process, and Tips

Find the median of a subarray in a given array.

• Sort the subarray and find the middle element for odd length subarrays.

• For even length subarrays, find the average of the middle two elements.

• Use a sliding window approach to iterate through all subarrays.

Sorting array of strings

• Use Arrays.sort() method to sort the array in ascending order

• Use Comparator.reverseOrder() to sort the array in descending order

• Implement your own sorting algorithm if required

Java is a programming language while Hibernate is an ORM tool for Java.

• Java is an object-oriented language used for developing applications.

• Hibernate is an ORM tool that simplifies database access for Java applications.

• Hibernate maps Java classes to database tables and provides a framework for querying and manipulating data.

• Hibernate reduces the amount of boilerplate code needed for database access in Java applications

OOPs is a programming paradigm based on the concept of objects.

• OOPs stands for Object-Oriented Programming.

• It focuses on creating objects that contain both data and functions.

• Encapsulation, Inheritance, and Polymorphism are the three main pillars of OOPs.

• Java, C++, Python, and Ruby are some of the popular OOPs languages.

• Example: A car can be an object with properties like color, model, and functions like start, stop, a

Java 8 introduced several new features including lambda expressions, streams, and functional interfaces.

• Lambda expressions allow for functional programming and simplify code.

• Streams provide a way to process collections of data in a declarative way.

• Functional interfaces enable the use of lambda expressions and method references.

• Default methods allow for adding new methods to interfaces without breaking existing implemen...read more

Array is a fixed size data structure while ArrayList is a dynamic size data structure in Java.

• Array is a primitive data type while ArrayList is a class in Java.

• Array can hold only homogeneous data types while ArrayList can hold heterogeneous data types.

• Array needs to be initialized with a fixed size while ArrayList can be initialized without a size.

• Array uses [] brackets to declare while ArrayList uses <> brackets to d...read more

Collection framework is a set of classes and interfaces that provide a way to store and manipulate groups of objects.

• It includes interfaces like List, Set, and Map

• It provides implementations like ArrayList, HashSet, and HashMap

• It simplifies the process of storing and manipulating data

• It allows for easy iteration and sorting of collections

• Example: List names = new ArrayList<>();

• Example: Map ages = new H

Marker interface is an interface with no methods, used to mark a class as having a certain property or behavior.

• Marker interfaces are used for metadata purposes.

• They are used to provide information to the compiler or runtime environment.

• Examples of marker interfaces in Java include Serializable, Cloneable, and Remote.

• Marker interfaces can also be used to enforce design patterns, such as the Decorator pattern.

Thread is a lightweight sub-process, a separate path of execution within a program.

• Threads allow concurrent execution of two or more parts of a program.

• Java provides built-in support for multithreading through the Thread class and Runnable interface.

• Threads can be created by extending the Thread class or implementing the Runnable interface.

• Thread.sleep() method is used to pause the execution of a thread for a specified...read more

JDBC is a low-level API for connecting to databases, while Hibernate is a high-level ORM framework.

• JDBC requires manual coding for CRUD operations, while Hibernate provides automatic mapping of objects to database tables.

• JDBC is more suitable for small-scale applications, while Hibernate is better for large-scale applications.

• Hibernate provides caching and lazy loading, which improves performance, while JDBC does not h...read more

String buffer is synchronized while string builder is not.

• String buffer is thread-safe while string builder is not.

• String buffer is slower than string builder.

• String builder is preferred for single-threaded operations.

• Both classes are used for manipulating strings.

• Example: StringBuffer sb = new StringBuffer(); StringBuilder sb = new StringBuilder();

Microservices is an architectural style that structures an application as a collection of small, independent services.

• Microservices are independently deployable and scalable.

• Each microservice focuses on a specific business capability.

• Communication between microservices is usually done through APIs.

• Microservices can be developed using different programming languages and technologies.

• Examples of companies using microserv

Constructor chaining is calling one constructor from another constructor within the same class.

• It allows to reuse the code of one constructor in another constructor.

• It is achieved using the 'this' keyword followed by the constructor parameters.

• It can be used to set default values or to initialize variables before calling another constructor.

• Example: public MyClass(int x) { this(x, 0); } public MyClass(int x, int y) { t

Exception handling is a mechanism to handle runtime errors. There are two types of exceptions: checked and unchecked.

• Checked exceptions are checked at compile-time and must be handled or declared in the method signature.

• Unchecked exceptions are not checked at compile-time and can be handled using try-catch or thrown to the calling method.

• Common exceptions include NullPointerException, ArrayIndexOutOfBoundsException, an...read more

HTTP servlet is a Java class that extends the capabilities of servers that host applications accessed by HTTP protocol.

• HTTP servlet is a Java class that extends the capabilities of servers that host applications accessed by HTTP protocol

• It is used to handle HTTP requests and responses

• It provides methods to get information about the request and to send a response back to the client

• It can be used to create dynamic web pa...read more

List is an ordered collection of elements while Set is an unordered collection of unique elements.

• List allows duplicate elements while Set does not.

• List maintains the insertion order while Set does not guarantee any order.

• List is implemented by ArrayList, LinkedList, etc. while Set is implemented by HashSet, TreeSet, etc.

• Example: List - [1, 2, 3, 3, 4], Set - [1, 2, 3, 4]