TCS Java Developer Interview Questions and Answers for Experienced

Transient variables are not serialized, so they are not transmitted over the network during serialization.

• Transient variables are marked with the 'transient' keyword in Java.

• They are excluded from the serialization process, meaning their values are not saved.

• Example: If a class has a transient variable 'password', it won't be serialized.

• When the object is deserialized, transient variables will have their default values...read more

A controller handles specific requests, while a front controller centralizes request handling for an entire application.

• A controller is responsible for processing user input and returning the appropriate response.

• A front controller acts as a single entry point for handling requests, delegating to specific controllers.

• Example of a controller: In a Spring MVC application, a specific controller class handles requests for ...read more

To find the second highest salary, we can use various methods like sorting, using a set, or iterating through the dataset.

• 1. Sort the salaries in descending order and pick the second element.

• Example: [3000, 2000, 4000] -> Sorted: [4000, 3000, 2000] -> Second highest: 3000

• 2. Use a Set to remove duplicates, then sort.

• Example: [3000, 2000, 3000, 4000] -> Set: [3000, 2000, 4000] -> Sorted: [4000, 3000, 20...read more

@Qualifier is an annotation in Spring Framework used to resolve ambiguity when multiple beans of the same type exist.

• @Qualifier is used in dependency injection to specify which bean to inject when multiple candidates are available.

• It can be applied to fields, methods, and constructor parameters.

• Example: @Autowired @Qualifier("beanName") private MyBean myBean;

• It helps in improving code readability and maintainability by...read more

OOP concepts like encapsulation, inheritance, and polymorphism were integral to our Java project, enhancing code modularity and reusability.

• Encapsulation: We used private fields in classes and provided public getter and setter methods to control access.

• Inheritance: Created a base class 'Animal' and derived classes 'Dog' and 'Cat' to share common behavior.

• Polymorphism: Implemented method overriding in subclasses to prov...read more

Exceptions are issues that can be handled, while Errors are serious problems that usually cannot be recovered from.

• Exceptions are checked at compile-time, while Errors are unchecked.

• Examples of Exceptions: IOException, SQLException.

• Examples of Errors: OutOfMemoryError, StackOverflowError.

• Exceptions can be caught and handled using try-catch blocks.

• Errors indicate serious problems that a reasonable application should not...read more

Collections in Java are frameworks that provide an architecture to store and manipulate groups of objects.

• 1. Types of Collections: List, Set, Map, Queue.

• 2. List: Ordered collection, allows duplicates. Example: ArrayList, LinkedList.

• 3. Set: Unordered collection, no duplicates. Example: HashSet, TreeSet.

• 4. Map: Key-value pairs, no duplicate keys. Example: HashMap, TreeMap.

• 5. Queue: Ordered collection for processing eleme...read more

VARCHAR2 is a variable-length character data type in SQL, primarily used in Oracle databases to store strings.

• VARCHAR2 can store up to 4000 bytes of character data.

• It is used for storing variable-length strings, optimizing storage space.

• Example: VARCHAR2(50) can store a string of up to 50 characters.

• VARCHAR2 is sensitive to character set and can store multi-byte characters.