Java SE and EE Overview

Definition: Core Java platform used for developing desktop applications and applets.
Key Components:
- Java Language: Object-oriented programming language.
- Java Virtual Machine (JVM): Platform-independent execution environment for Java bytecode.
- Java Development Kit (JDK): Tools for developing Java applications (compiler, debugger, etc.).
APIs: Rich set of APIs for I/O, networking, utilities, XML parsing, and more.
Features:
- Multithreading: Built-in support for concurrent programming.
- Exception Handling: Robust error handling capabilities.

Definition: A set of specifications for enterprise features and web services.
Key Specifications:
- Servlets and JSP: For building dynamic web applications.
- EJB (Enterprise JavaBeans): For building scalable, transactional applications.
- JPA (Java Persistence API): For database access and management.
- JAX-RS and JAX-WS: For RESTful and SOAP web services.
Application Server: Requires an application server (e.g., WildFly, GlassFish) to run.

Spring Framework:
- Inversion of Control (IoC) and Dependency Injection.
- Comprehensive programming model for building Java applications.
Hibernate:
- ORM framework for database interactions.
- Facilitates mapping Java objects to database tables.
JavaServer Faces (JSF):
- Component-based web framework for building UI.
- Simplifies the development of Java EE applications.
Apache Struts:
- Model-View-Controller (MVC) framework for creating web applications.

Core Collections:
- List: Ordered collection (ArrayList, LinkedList).
- Set: Unordered collection with no duplicates (HashSet, TreeSet).
- Map: Key-value pairs for associating data (HashMap, TreeMap).
Advanced Structures:
- Queue: FIFO structure (LinkedList, PriorityQueue).
- Stack: LIFO structure (Stack class, Deque).
Performance: Understand time complexity for operations (e.g., O(1) for insertion in HashMap).

Creational Patterns:
- Singleton: Restricts instantiation to one object.
- Factory Method: Creates objects without specifying the exact class.
Structural Patterns:
- Adapter: Allows incompatible interfaces to work together.
- Decorator: Adds functionality to objects dynamically.
Behavioral Patterns:
- Observer: Defines a dependency between objects, allowing one to notify others of changes.
- Strategy: Enables selecting an algorithm at runtime.
Best Practices: Promote code reusability and maintainability.

Java SE is the core Java platform for developing desktop applications and applets.
Java SE includes:
- Java Language: An object-oriented programming language.
- Java Virtual Machine (JVM): A platform-independent execution environment for Java bytecode.
- Java Development Kit (JDK): Tools for developing Java applications, including a compiler, debugger, and other tools.
- APIs: A rich collection of Application Programming Interfaces (APIs) provides functionality for input/output (I/O), networking, utilities, XML parsing, and more.
Java SE features:
- Multithreading: Built-in support for concurrent programming.
- Exception Handling: Robust error handling capabilities.

Java EE is a set of specifications for enterprise features and web services.
Key Java EE specifications include:
- Servlets and JSP: These technologies are used to build dynamic web applications.
- EJB (Enterprise JavaBeans): Used for building scalable and transactional applications.
- JPA (Java Persistence API): Used for database access and management.
- JAX-RS and JAX-WS: Frameworks for developing RESTful and SOAP web services.
Java EE applications require an application server (e.g., WildFly, GlassFish) to run.

Java frameworks streamline development and provide a structured approach to building applications.
Popular Java frameworks include:
- Spring Framework:
  - Employs Inversion of Control (IoC) and Dependency Injection for a flexible and modular architecture.
  - Offers a comprehensive programming model for building Java applications.
- Hibernate:
  - An Object-Relational Mapping (ORM) framework.
  - Enables mapping Java objects to database tables, simplifying data persistence.
- JavaServer Faces (JSF):
  - A component-based web framework for building user interfaces (UIs).
  - Simplifies the development of Java EE applications by providing reusable UI components.
- Apache Struts:
  - A Model-View-Controller (MVC) framework for creating robust and scalable web applications.

Data structures are essential for organizing and accessing data efficiently.
Core Java Collections Framework:
- List: An ordered collection (ArrayList and LinkedList).
- Set: An unordered collection that doesn't allow duplicates (HashSet and TreeSet).
- Map: Key-value pairs for associating data (HashMap and TreeMap).
Advanced Data Structures:
- Queue: A First-In, First-Out (FIFO) structure (LinkedList and PriorityQueue)
- Stack: A Last-In, First-Out (LIFO) structure (Stack Class and Deque)
Performance: Understanding the time complexity (e.g., O(1) for insertion in HashMap) of data structure operations is crucial for efficient code.

Design patterns are reusable solutions to common software design problems.
Creational Patterns:
- Singleton: Ensures that only one instance of a class can be created.
- Factory Method: Creates objects without specifying the exact class.
Structural Patterns:
- Adapter: Allows incompatible interfaces to work together.
- Decorator: Dynamically adds functionality to objects.
Behavioral Patterns:
- Observer: Defines a dependency between objects where one object (the subject) notifies others (observers) of changes.
- Strategy: Enables selecting an algorithm at runtime.
Java design patterns promote code reusability and maintainability, leading to more robust and well-designed software.