Learning Path

Java Roadmap A to Z

A practical path to go from Java fundamentals to building, testing, and shipping real backend systems.

Foundations

Java Origins, Versions and LTS

  • History of Java and JVM ecosystem
  • Release cadence and versioning model
  • What LTS means and when to upgrade
  • Current Java language state
  • Where Java is used (software, backend, Android)
Open Tutorial >

Foundations

Install JDK and Tooling

  • Install JDK 21+
  • Set JAVA_HOME/PATH
  • Use IntelliJ or VS Code
Open Tutorial >

Core Syntax

JVM, JDK, JRE Mental Model

  • How bytecode works
  • Class loading basics
  • Compilation vs runtime
Open Tutorial >

Language Basics

Variables, Types, Operators

  • Primitives vs wrappers
  • Type casting
  • Arithmetic and logical ops
Open Tutorial >

Language Basics

Control Flow

  • if/else, switch
  • for/while/do-while
  • break, continue, return
Open Tutorial >

Language Basics

Methods and Parameters

  • Method signatures
  • Pass-by-value behavior
  • Overloading
Open Tutorial >

OOP

Classes and Objects

  • Fields and constructors
  • Instance vs static members
  • Encapsulation
Open Tutorial >

OOP

Inheritance and Polymorphism

  • extends, super
  • Method overriding
  • Dynamic dispatch
Open Tutorial >

OOP

Interfaces and Abstract Classes

  • Contract-first design
  • Default/static methods
  • Composition over inheritance
Open Tutorial >

Error Handling

Exceptions

  • Checked vs unchecked
  • try/catch/finally
  • Custom exception types
Open Tutorial >

Core APIs

Strings and Date/Time

  • StringBuilder, immutability
  • java.time API
  • Formatting and parsing
Open Tutorial >

Core APIs

Collections Fundamentals

  • List, Set, Map
  • When to use each
  • Big-O basics
Open Tutorial >

Core APIs

Generics

  • Type parameters
  • Wildcards ? extends/super
  • Generic methods
Open Tutorial >

Core APIs

Enum, Record, Sealed Classes

  • Model finite states
  • Immutable DTOs with record
  • Restrict inheritance
Open Tutorial >

Functional Java

Lambdas and Functional Interfaces

  • Predicate, Function, Consumer
  • Method references
  • Higher-order style
Open Tutorial >

Functional Java

Streams

  • map/filter/reduce
  • Collectors
  • Avoid overusing streams
Open Tutorial >

Functional Java

Optional

  • Null-safe flow
  • map/flatMap/orElse
  • API boundaries best practices
Open Tutorial >

I/O

Files, Paths, NIO.2

  • Read/write files
  • Directory traversal
  • Buffered APIs
Open Tutorial >

Concurrency

Threads and Synchronization

  • Thread lifecycle
  • synchronized and locks
  • Race conditions
Open Tutorial >

Concurrency

ExecutorService

  • Thread pools
  • Callable/Future
  • Graceful shutdown
Open Tutorial >

Concurrency

CompletableFuture

  • Async pipelines
  • Error handling
  • Composing async tasks
Open Tutorial >

Build Tooling

Maven or Gradle

  • Dependency scopes
  • Plugins and lifecycle
  • Profiles
Open Tutorial >

Data

SQL Fundamentals

  • Joins and indexes
  • Transactions
  • Query optimization basics
Open Tutorial >

Data

JDBC

  • Connections and statements
  • Prepared statements
  • Mapping results
Open Tutorial >

Data

JPA/Hibernate

  • Entity mapping
  • Lazy vs eager loading
  • N+1 and transaction boundaries
Open Tutorial >

Backend

Backend API Essentials

  • Layered architecture
  • Configuration and validation
  • Error handling contracts
Open Tutorial >

Security

Application Security Basics

  • AuthN/AuthZ concepts
  • Token/session approaches
  • Endpoint hardening
Open Tutorial >

Testing

JUnit 5 + Mockito

  • Unit tests
  • Mocks and stubs
  • Test naming and structure
Open Tutorial >

Delivery

Docker + CI/CD

  • Containerize app
  • Build pipelines
  • Deploy strategies
Open Tutorial >

Production

Observability and Performance

  • Structured logs
  • Metrics and tracing
  • Profiling and tuning
Open Tutorial >

From the Blog

Related to Java

A selection of three blog posts whose title contains Java.

View all
Understanding DTOs in Java Spring Boot banner

13/01/2025 · 3 min

Understanding DTOs in Java Spring Boot

In Java Spring Boot development, **DTO** (Data Transfer Object) is a common design pattern used to transfer data between different layers of an application. This pattern is especially useful in complex systems where entit

#spring-boot #java
open >
Introduction to Maven in a Java Spring Boot project banner

08/01/2025 · 7 min

Introduction to Maven in a Java Spring Boot project

[Apache Maven](https://maven.apache.org/) is a powerful build automation and dependency management tool widely used in Java development. When working on a Spring Boot project, Maven simplifies project setup, dependency ma

#spring-boot #java
open >
Primitive types and wrapper classes in Java banner

19/12/2024 · 4 min

Primitive types and wrapper classes in Java

Java is a statically typed programming language that supports both primitive data types and objects. While primitive types are fundamental to the language, their object equivalents—known as wrapper classes—are critical fo

#java
open >