JAVA

Java

Java 21+Beginner → Intermediate → Advanced

Learn modern Java from your first program to production services — classes, records, collections, streams, exceptions, Maven and JUnit, concurrency and virtual threads, JDBC, Spring Boot and the JVM.

1. Beginner8 lessons

Start from zero with Java: install the JDK, run your first program, and learn the fundamentals — types, decisions, loops, methods, arrays, strings and your first classes. All examples run with Java 21 using a single `java File.java` command.

You will be able to

  • Install the JDK and compile and run Java programs
  • Use primitive types, String, var and type conversion correctly
  • Write conditions, switch expressions, loops and methods
  • Work with arrays and strings, and define simple classes

Lessons

  1. Setting up Java
  2. Variables, Types & Strings
  3. Decisions, Switch & Loops
  4. Methods
  5. Arrays & Strings
  6. Classes & Objects
  7. Reading Input with Scanner
  8. Dates & Times with java.time
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2. Intermediate9 lessons

Write modern, idiomatic Java: design with interfaces and polymorphism, model data with records, enums and sealed types, master the Collections framework and generics, handle exceptions properly, process data with lambdas and streams, and work with files.

You will be able to

  • Design with inheritance, abstract classes and interfaces
  • Model data with records, enums, sealed interfaces and pattern matching
  • Use List, Map, Set and generics confidently
  • Handle exceptions, write stream pipelines and read and write files

Lessons

  1. Inheritance, Interfaces & Polymorphism
  2. Records, Enums, Sealed Types & Pattern Matching
  3. The Collections Framework
  4. equals, hashCode & Comparable
  5. Generics
  6. Exceptions
  7. Lambdas, Optional & Streams
  8. Regular Expressions & Text Processing
  9. Files & I/O with java.nio
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3. Advanced9 lessons

Build and run professional Java systems: Maven projects with JUnit tests, concurrency with executors, CompletableFuture and virtual threads, thread safety, HTTP clients and servers, PostgreSQL with JDBC, REST APIs with Spring Boot, and packaging and tuning the JVM for production.

You will be able to

  • Structure Maven projects and test them with JUnit
  • Write correct concurrent code with executors, CompletableFuture and virtual threads
  • Call and serve HTTP, and use PostgreSQL safely through JDBC
  • Build a validated REST API with Spring Boot and ship it to production

Lessons

  1. Maven Projects & Testing with JUnit
  2. Concurrency: Executors & CompletableFuture
  3. Virtual Threads & Thread Safety
  4. HTTP: HttpClient & a Built-in Server
  5. Databases with JDBC & PostgreSQL
  6. REST APIs with Spring Boot
  7. Spring Data JPA with PostgreSQL
  8. Packaging, the JVM & Production
  9. Project: Results Portal API
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