Java and Object-Oriented Programming (OOP)

Overview

• Importance of Java in software development
• Discussion on OOP concepts
• Total topics coverage: 506, 509, and KE 220

Core Java Concepts

Methods in Classes

• Methods with the same name in a class
• Overloaded methods can differ by the number and type of parameters
• Return type variations

Constructors and Object Creation

• Creation of objects using constructors
• Java’s support for constructor overloading
• Constructors are defined in the class

Abstract Classes and Interfaces

Abstract Classes

• Not totally abstract; can have predefined methods (concrete methods)
• Used for a base class to be inherited by other classes

Interfaces

• All methods are abstract by default in interfaces (though from Java 8, default and static methods are supported)
• Used to ensure a class implements specific methods
• Difference between abstract classes and interfaces is mainly in their use-case and behavior

Exception Handling

• Importance of handling run-time exceptions
• Poor practice examples and correct methods
• Use of try-catch blocks
• Importance in maintaining the smooth flow of the application

Collections in Java

Lists and Sets

• Use of ArrayList, LinkedList, HashSet, etc.
• Understanding Comparable and Comparator
• Comparable: used to define natural ordering within a class
• Comparator: used for defining multiple ways to compare objects

Equality Check in Java

• equals() method vs. ==
• equals() method: Used for logical comparisons
• == operator: Checks if two references point to the same object

Advanced Java Topics

Usage of Optional

• Optional class to avoid null references
• Methods like .isPresent(), .ifPresent(), .orElse(), and .orElseThrow()

Lambda Functions and Streams

• Introduction of lambda functions in Java 8
• Use cases and examples
• Stream API for collection processing

Marker Interface

• Purpose and usage of Marker interfaces
• Examples: Serializable, Cloneable

Practical Questions and Examples

Query Execution

• Writing SQL queries in Java applications
• Practical SQL usage with Java Standard Libraries

Multithreading

• Multithreaded environments, synchronization, and concurrent collections
• Practical issues and best practices

Microservices with Spring Boot

• Introduction to microservices architecture
• Key components and annotations in Spring Boot
• RESTful services and controllers

Database Connectivity

• Establishing database connections using Java
• Configuration and usage in Spring Boot

Configuration and Externalization

• Managing external configurations in Java applications
• Property files and their usage in different deployment environments

Miscellaneous Topics

• Handling duplicates in collections
• Binary search and sorting algorithms in Java
• Use of design patterns
• General best practices in Java programming