Basic Java Programming

Section 1: Lab: Getting Started with Java 25 LTS and Its Tools

• How the JDK, the JVM and bytecode work together, and the Java LTS release cycle
• Install JDK 25 and set up IntelliJ IDEA or VS Code
• Try code in jshell and run a .java file directly without a separate compile step
• Compact source files and instance main methods for short programs
• Lab: a first program in the short form compared with a full class

Section 2: Java Syntax Compared with the Languages You Know

• Primitive and reference types, var and type conversion
• Strings, text blocks and formatting with formatted()
• if, loops and switch expressions that return a value
• Methods, overloading and pass by value
• Lab: port a short program from your usual language to Java

Section 3: Classes, Objects and Encapsulation

• Fields, methods, constructors and the this keyword
• static, final and access modifiers
• Packages and organising code in a project
• Flexible constructor bodies to validate values before calling super()
• Lab: a customer account class that validates its own data

Section 4: Inheritance, Interfaces and Polymorphism

• extends, overriding and super
• Abstract classes compared with interfaces and default methods
• Sealed classes and sealed interfaces to restrict subtypes
• Polymorphism and when to prefer composition over inheritance
• Lab: a shipping cost calculator with several strategies behind an interface

Section 5: Lab: Records, Enums and Pattern Matching

• Records for immutable data instead of classes with hand-written getters
• Enums with fields and methods
• Pattern matching with instanceof and switch
• Record patterns and unnamed variables (_)
• Lab: handle orders in several states with a sealed interface and switch

Section 6: Generics and the Collections Framework

• Generics and why they reduce type errors
• List, Set and Map, and choosing ArrayList, HashSet, HashMap or TreeMap for the job
• Sequenced collections with getFirst(), getLast() and reversed()
• Unmodifiable collections with List.of() and Map.of()
• Lab: a shopping cart that uses several collection types

Section 7: Lab: Lambdas, the Stream API and Optional

• Functional interfaces, lambdas and method references
• Streams: filter, map, sorted and collect
• Group and summarise data with Collectors.groupingBy
• Optional for values that may be absent instead of returning null
• Lab: summarise sales by product category from a list of orders

Section 8: Exceptions, Logging and Debugging

• Checked and unchecked exceptions and when to use each
• try-with-resources and creating your own exceptions
• Read stack traces and use the IDE debugger
• Log with System.Logger instead of printing with println
• Lab: add error handling to the shopping cart

Section 9: Lab: Files, Dates and JSON

• Read and write files with Path and Files (NIO.2)
• Read a CSV file line by line and map it to records
• Dates and times with java.time: LocalDate, LocalDateTime and ZonedDateTime
• Convert objects to and from JSON with the Jackson library
• Lab: import product data from CSV and export it as JSON

Section 10: Lab: Maven and Unit Testing with JUnit 6

• Maven project layout, pom.xml and adding dependencies
• Common build commands: compile, test and package
• Write tests with JUnit 6 and readable assertions with AssertJ
• Parameterised tests to cover many cases at once
• Lab: write tests for the price and discount calculations

Section 11: Lab: Database Access with JDBC

• Run PostgreSQL with Docker and add the JDBC driver through Maven
• Connection, PreparedStatement and ResultSet
• Prevent SQL injection with parameters instead of string concatenation
• Transactions and moving database code into a repository
• Lab: save and search product data in the database

Section 12: Concurrency with Threads and Virtual Threads

• Threads, Runnable and race conditions
• ExecutorService and CompletableFuture
• Virtual threads for large numbers of I/O-bound tasks
• Protect shared data with locks and ConcurrentHashMap
• Lab: process several files concurrently and combine the results

Section 13: Lab: Calling REST APIs with HttpClient

• HttpClient, HttpRequest and HttpResponse in the standard library
• Synchronous and asynchronous API calls
• Map JSON responses to records with Jackson
• Handle timeouts, status codes and errors from external APIs
• Lab: fetch exchange rates or other public data into the program

Section 14: Packaging the App and Next Steps

• Build a runnable JAR file with Maven
• Configure the app through environment variables and properties files
• An overview of running Java applications in Docker
• Next steps towards Spring Boot, Jakarta EE and backend work

Section 15: Workshop: Inventory Management Capstone

• Design the records, interfaces and repositories of the system
• Import data from CSV and store it in PostgreSQL with JDBC
• Produce summary reports with the Stream API and export them as JSON
• Write unit tests for the key parts and package the app as a JAR
• Present the work, review the code together and plan next steps