Learning paths

Java from zero

Install Java and write real programs, then learn objects, collections and the modern Java basics every job expects.

  • For: You have never programmed, or you are new to Java.
  • By the end: You can write, run, debug and test small Java programs on your own.
  • Size: 25 lessons (1 h 19 min of reading, plus time to try the code), beginner
Start with How Java runs: JDK, JRE and JVM
  1. Variables and data typesJava fundamentals, beginner, 3 min
  2. Operators and expressionsJava fundamentals, beginner, 3 min
  3. Control flow and the modern switchJava fundamentals, beginner, 3 min
  4. Loops and arraysJava fundamentals, beginner, 3 min
  5. Methods and pass-by-valueJava fundamentals, beginner, 3 min
  6. Strings, StringBuilder and text blocksJava fundamentals, beginner, 4 min
  7. Reading input and formatting outputJava fundamentals, beginner, 3 min
  8. Numbers: Math, BigDecimal and random valuesJava fundamentals, beginner, 3 min
  9. RecursionJava fundamentals, beginner, 3 min
  10. Classes, objects and constructorsObject-oriented programming, beginner, 3 min
  11. static, final and constantsObject-oriented programming, beginner, 3 min
  12. Packages, imports and project structureObject-oriented programming, beginner, 3 min
  13. Encapsulation, inheritance and polymorphismObject-oriented programming, beginner, 3 min
  14. Abstract classes vs interfacesObject-oriented programming, intermediate, 3 min
  15. Enums in depthObject-oriented programming, intermediate, 3 min
  16. Records, enums and sealed typesObject-oriented programming, intermediate, 3 min
  17. Exception handlingCore APIs, intermediate, 5 min
  18. Collections framework: choosing the right oneCore APIs, intermediate, 3 min
  19. Lists, sets and queues in practiceCore APIs, intermediate, 3 min
  20. Generics and wildcardsCore APIs, intermediate, 3 min
  21. Lambdas and functional interfacesModern Java, intermediate, 3 min
  22. Stream APIModern Java, intermediate, 3 min
  23. Clean code: naming, methods and refactoringDesign and clean code, beginner, 3 min
  24. Debugging and reading stack tracesTools and testing, beginner, 3 min

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