A Java Full Stack Developer refers to a developer who is proficient in both frontend and backend technologies, working with Java for the backend, and various technologies for the frontend. The term "full stack" implies that they can manage the entire software development process, from the user interface (UI) to the database.

1. Backend (Server-Side) Technologies:
In the context of a Java Full Stack Developer, the backend typically involves working with Java and related frameworks and tools to handle the business logic, data storage, and server-side operations.

Core Java: The foundation of backend development. Knowledge of Java SE (Standard Edition) is crucial for writing the server-side code.

Java EE (Jakarta EE): This includes tools and libraries for building enterprise-level applications, such as servlets, JSP, and EJB.

Spring Framework: One of the most popular frameworks for building backend applications in Java. It provides:

Spring Boot: For easy application setup and microservice architecture.
Spring MVC: For creating web applications with the Model-View-Controller (MVC) pattern.
Spring Security: For authentication and authorization.
Spring Data/JPA: For working with databases using Java Persistence API (JPA) and simplifying database operations.
Spring Cloud: For building distributed systems and microservices.
Hibernate: A framework for object-relational mapping (ORM) in Java, allowing developers to map Java objects to database tables.

Databases:

SQL Databases: Typically, a Java Full Stack Developer works with relational databases like MySQL, PostgreSQL, or Oracle. Knowledge of SQL is essential for handling CRUD operations.
NoSQL Databases: Sometimes, NoSQL databases like MongoDB are used depending on the application requirements.
2. Frontend (Client-Side) Technologies:
For the frontend, a Java Full Stack Developer needs to be familiar with technologies that handle the UI and user interaction.

HTML5, CSS3, and JavaScript: The building blocks of the web. HTML for structure, CSS for styling, and JavaScript for dynamic functionality.

JavaScript Frameworks/Libraries:

Angular: A powerful front-end framework that works well with Java backend services. It uses TypeScript and provides tools for building single-page applications (SPAs).
React: A popular JavaScript library for building user interfaces. React focuses on creating reusable UI components.
Vue.js: A progressive JavaScript framework for building modern UIs, which is known for its simplicity and flexibility.
AJAX: For asynchronous communication between the frontend and backend, allowing data to be fetched from the server without reloading the page.

CSS Frameworks: Tools like Bootstrap or Tailwind CSS help developers build responsive and aesthetically pleasing UI designs quickly.

3. DevOps & Tools:
A Java Full Stack Developer also works with DevOps tools to manage and deploy applications, ensuring that the app runs efficiently in production environments.

Version Control: Tools like Git and platforms like GitHub or GitLab for managing code versions and collaboration.

Build Tools:

Maven and Gradle are build automation tools that are commonly used for managing Java projects and their dependencies.
CI/CD (Continuous Integration/Continuous Deployment): Tools like Jenkins or GitLab CI help automate the process of testing and deploying applications.

Containerization and Virtualization: Docker and Kubernetes are used to package applications into containers for easier deployment and scaling.

4. RESTful Web Services & APIs:
RESTful APIs: A Java Full Stack Developer needs to be skilled in creating and consuming RESTful APIs for communication between the frontend and backend. They need to understand HTTP methods (GET, POST, PUT, DELETE), status codes, and request/response formats (typically JSON).

JSON: The primary format for data exchange between the backend and frontend. Understanding how to parse and generate JSON is crucial.

5. Testing:
Testing is an essential part of any full stack development process.

Unit Testing (JUnit): Testing individual components or methods in Java.

Integration Testing: Testing how different parts of the system interact.

Frontend Testing: Tools like Jest (for React) or Karma (for Angular) for testing frontend code.

End-to-End Testing: Tools like Selenium or Cypress for automating and testing the entire application flow.

6. Soft Skills and Tools:
Problem-Solving: Full stack developers must be good at troubleshooting issues across both frontend and backend.

Collaboration: They often work with other developers, designers, and product managers, so communication and collaboration skills are important.

Agile Methodologies: Many teams use agile development practices, so understanding Scrum or Kanban processes can be beneficial.

Typical Workflow for Java Full Stack Developer:
Frontend Development:

Build the user interface using HTML, CSS, and JavaScript (or a JavaScript framework like Angular/React).
Backend Development:

Set up the server and write the backend logic using Java (Spring Boot, Hibernate, etc.).
Set up and manage the database (using SQL/NoSQL).
Build and expose RESTful APIs that the frontend can consume.
Connecting Frontend to Backend:

Use AJAX/REST to enable communication between the frontend and backend.
Consume the backend API on the frontend and handle the responses.
Deployment and Maintenance:

Use tools like Jenkins for continuous integration and Git for version control.
Deploy the application using containerization tools like Docker and Kubernetes.