Java JVM Developer

Core Java Fundamentals

Strengthen understanding of Object-Oriented Programming (OOP) — encapsulation, inheritance, polymorphism, and abstraction.

Review the Collections Framework, including List, Set, Map, and their common implementations (ArrayList, HashSet, HashMap).

Practice using Java Streams and Lambda Expressions for filtering, mapping, and transforming collections.

Revise exception handling, interfaces, abstract classes, and Java data types.

Focus on writing clean, readable, and efficient code.   2.  Spring and Dependency Injection

Deepen knowledge of the Spring Framework, especially dependency injection and how beans are created and managed.

Understand Spring Boot annotations such as @Component, @Service, @Repository, @Autowired, and @Bean.

Learn about IoC (Inversion of Control) and bean lifecycle.

Build small demo projects using Spring Boot with REST APIs, configuration properties, and application contexts.   3.  Programming and Problem Solving

Practice solving logic-based programming questions such as:

Filtering numbers (e.g., selecting even numbers from a list).

Basic search and update operations in data structures like arrays, lists, and trees.

Work on tree-based problems — traversal (inorder, preorder, postorder), searching, and replacing values.

Strengthen algorithmic thinking — break down problems step by step before coding.

Use platforms like LeetCode, HackerRank, or GeeksforGeeks for structured practice.   4.  Coding Practice and Approach

Write and test code in an IDE like IntelliJ or Eclipse, but also practice writing without auto-complete to improve recall.

Focus on explaining your thought process during coding — interviewers evaluate reasoning as much as the result.

Practice converting logical steps into working Java code confidently.   5.  End-to-End Application Thinking

Understand how Spring beans interact within a project, from service to controller.

Be ready to explain how data flows through a typical Spring Boot application (request → controller → service → repository → database).