Fresher Level Learning Plan (0-2 years):
Month 1-2: Core Java (syntax, OOPs, data types)
Month 3-4: Collections Framework (List, Set, Map)
Month 5-6: Exception Handling, I/O, and Streams
Month 7-8: Basics of Multithreading and Concurrency
Month 9-10: JDBC and Database Connectivity
Month 11-12: Build 3-4 small projects (console-based)

Recommended Certifications:
- Oracle Certified Associate (OCA) Java
- Java Programming for Beginners (Udemy)

// Example: Java OOPs and Collections
import java.util.*;

class Employee {
    private int id;
    private String name;
    public Employee(int id, String name) {
        this.id = id;
        this.name = name;
    }
    public String toString() {
        return "Employee{id=" + id + ", name='" + name + "'}";
    }
}

public class Main {
    public static void main(String[] args) {
        List empList = new ArrayList<>();
        empList.add(new Employee(101, "Rahul"));
        empList.add(new Employee(102, "Priya"));
        empList.add(new Employee(103, "Amit"));
        
        // Iterate and print
        for (Employee e : empList) {
            System.out.println(e);
        }
    }
}

Mid-Level Learning Plan (2-5 years):
Month 1-2: Spring Core (IoC, DI, AOP)
Month 3-4: Spring Boot (REST APIs, auto-config)
Month 5-6: Hibernate and JPA (ORM, relationships)
Month 7-8: Spring Data JPA, Query Methods
Month 9-10: Security (Spring Security, JWT)
Month 11-12: Microservices basics, Eureka, API Gateway

Recommended Certifications:
- Oracle Certified Professional (OCP) Java
- Spring Professional Certification (VMware)

// Spring Boot REST Controller Example
@RestController
@RequestMapping("/api/employees")
public class EmployeeController {
    
    @Autowired
    private EmployeeService service;
    
    @GetMapping
    public List getAllEmployees() {
        return service.findAll();
    }
    
    @PostMapping
    public Employee createEmployee(@RequestBody Employee emp) {
        return service.save(emp);
    }
    
    @GetMapping("/{id}")
    public ResponseEntity getById(@PathVariable Long id) {
        return service.findById(id)
            .map(ResponseEntity::ok)
            .orElse(ResponseEntity.notFound().build());
    }
}

Senior Level Learning Plan (5+ years):
Month 1-2: Microservices with Spring Cloud
Month 3-4: Docker and Kubernetes for Java apps
Month 5-6: Cloud deployment (AWS, Azure, GCP)
Month 7-8: System Design (caching, messaging, databases)
Month 9-10: Event-driven architecture (Kafka, RabbitMQ)
Month 11-12: Lead projects, mentor juniors, architect solutions

Recommended Certifications:
- AWS Certified Solutions Architect
- Spring Cloud / Microservices Certification
- Kubernetes Administrator (CKA)

# Dockerfile for a Spring Boot app
FROM openjdk:17-jdk-slim
VOLUME /tmp
COPY target/myapp.jar app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "/app.jar"]

Fresher Skills (0-2 years):
- Core Java (Syntax, OOPs, Collections)
- Exception Handling and I/O
- Basic Multithreading
- JDBC and SQL
- Basics of Git and Version Control
- Problem-solving and Algorithms

Certifications:
- Oracle Certified Associate (OCA) Java
- Java Programming for Beginners (Udemy)

Projects:
- Console-based applications (e.g., Library Management, ATM Simulator)
- Simple CRUD applications with JDBC

Mid-Level Skills (2-5 years):
- Spring Boot, Spring MVC
- Hibernate / JPA
- RESTful API Development
- Unit Testing (JUnit, Mockito)
- Maven/Gradle build tools
- Basic Docker and CI/CD

Certifications:
- Oracle Certified Professional (OCP) Java
- Spring Professional Certification

Projects:
- Full-stack web application with Spring Boot + React/Angular
- REST API with Spring Security and JWT
- E-commerce or Inventory Management System

Senior/Expert Skills (5+ years):
- Microservices Architecture
- Spring Cloud (Eureka, Gateway, Config)
- Cloud Platforms (AWS, Azure, GCP)
- Containerization (Docker, Kubernetes)
- Message Queues (Kafka, RabbitMQ)
- System Design and Architecture
- Leadership and Mentoring

Certifications:
- AWS Certified Solutions Architect
- Kubernetes Administrator (CKA)
- Microservices Certification

Projects:
- Scalable microservices system
- Cloud-native application
- Event-driven architecture with Kafka