How to Prepare for Java Interview with Core Java, Java 8, Multithreading, Spring, Spring Boot, and Microservices (45 Days Plan)

To get ready for a Java interview, it’s important to have a well-organized study plan that focuses on important subjects like Java 8, Spring Framework, Spring Boot, and Microservices. This plan will help you learn and improve your understanding of these topics, making sure you’re fully prepared for the interview. Now, let’s take a look at a day-by-day study plan to guide your preparation.

Day 1–5: Core Java

• Day 1: Introduction to Java and its features. Understand the Java development environment setup and write basic programs. (2 hours)
• Day 2: Data types, variables, and operators in Java. Learn about primitive data types, reference types, and type conversion. (3 hours)
• Day 3: Control statements: if-else, switch-case, loops (for, while, do-while), and break/continue statements. Understand their syntax and usage. (4 hours)
• Day 4: Arrays in Java: Single-dimensional and multi-dimensional arrays. Learn how to declare, initialize, and manipulate arrays. (3 hours)
• Day 5: Object-oriented programming (OOP) concepts: Classes, objects, inheritance, polymorphism, and encapsulation. Understand the basics of OOP and their implementation in Java. (4 hours)

Day 6–10: Java 8

• Day 6: Introduction to Java 8 features: Lambda expressions and functional interfaces. Learn how to write and use lambda expressions. (3 hours)
• Day 7: Functional interfaces in Java 8: Predicate, Consumer, Function, Supplier. Understand their purpose and usage. (3 hours)
• Day 8: Stream API: Introduction to streams, stream creation, and stream operations (filter, map, reduce). Learn how to process collections using streams. (4 hours)
• Day 9: Optional class in Java 8: Handle null values effectively using Optional class. Understand its benefits and usage. (2 hours)
• Day 10: Default and static methods in interfaces: Explore the new possibilities introduced in Java 8 interfaces. Learn how to use default and static methods. (3 hours)

Day 11–15: Multithreading

• Day 11: Introduction to threads: Basics of multithreading, creating and starting threads in Java. (3 hours)
• Day 12: Thread synchronization: Learn about synchronized blocks and methods to ensure thread safety. Understand the concepts of locks and critical sections. (4 hours)
• Day 13: Thread communication: Explore mechanisms like wait(), notify(), and notifyAll() to coordinate threads and achieve synchronization. (3 hours)
• Day 14: Thread pools and Executors: Understand the benefits of thread pools and how to use the Executors framework for efficient thread management. (3 hours)
• Day 15: Concurrent collections: Explore concurrent collections like ConcurrentHashMap and ConcurrentLinkedQueue for thread-safe operations. (4 hours)

Day 16–20: Spring Framework

• Day 16: Introduction to the Spring Framework: Understand the core concepts, features, and benefits of using Spring. (3 hours)
• Day 17: Dependency Injection: Learn about different types of dependency injection (constructor, setter, and field injection) and their implementation in Spring. (4 hours)
• Day 18: Aspect-Oriented Programming (AOP): Understand AOP concepts, aspect-oriented programming in Spring, and how to use aspects for cross-cutting concerns. (4 hours)
• Day 19: Spring MVC: Explore the Model-View-Controller architecture and learn how to build web applications using Spring MVC. (5 hours)
• Day 20: Spring Data: Introduction to Spring Data and its support for various data access technologies. Learn how to integrate Spring Data with databases. (3 hours)

Day 21–25: Spring Boot

• Day 21: Introduction to Spring Boot: Understand the features and benefits of Spring Boot for rapid application development. Set up a basic Spring Boot project. (3 hours)
• Day 22: Auto-configuration: Learn how Spring Boot’s auto-configuration works and how to customize it. (3 hours)
• Day 23: Spring Boot starters: Explore the concept of starters and how they simplify dependency management in Spring Boot projects. (3 hours)
• Day 24: Spring Boot Actuator: Learn how to monitor and manage Spring Boot applications using Actuator endpoints. (3 hours)
• Day 25: Spring Boot Testing: Understand various testing approaches in Spring Boot, including unit testing, integration testing, and end-to-end testing. (4 hours)

Day 26–30: Microservices

• Day 26: Introduction to Microservices: Understand the principles, benefits, and challenges of Microservices architecture. (3 hours)
• Day 27: Service discovery: Learn how to implement service discovery using tools like Eureka or Consul. (4 hours)
• Day 28: Load balancing: Explore different load balancing techniques for distributing requests across Microservices instances. (3 hours)
• Day 29: Circuit breakers: Understand the concept of circuit breakers and their role in ensuring system resilience. (4 hours)
• Day 30: API gateways: Learn how to implement API gateways for routing, filtering, and securing Microservices APIs. (4 hours)

Day 31–45: Practice and Review

• Spend the remaining days practicing coding exercises, implementing small projects, and reviewing the topics you’ve covered so far.
• Solve interview-style coding problems, work on sample projects, and revise any weak areas.
• Allocate time for in-depth understanding of advanced concepts, such as advanced data structures, design patterns, and performance optimization techniques.
• Time dedicated: 3–4 hours per day.

Make sure to customize the study plan to match your own speed, schedule, and existing knowledge. Keep track of how well you’re progressing and modify the plan if necessary. Also, take advantage of online resources, tutorials, and books to enhance your learning experience.

If you want to learn Core Java from the beginning and that too without any cost, do checkout below Playlists:

Core Java

Spring Framework

Java 8

Java Interview Preparation