Java Programming

How Java programs are written, compiled and run, and the tools you need.

• What Java is and where it is used
• JDK, JRE and JVM
• Installing the JDK and an IDE
• The structure of a Java program and main()
• Compiling and running from the terminal
• Reading compiler errors

• What is Java?
• JDK, JRE and JVM

Storing values, the eight primitive types, String, and arithmetic and logical operators.

• Variables and naming rules
• Primitive types and their ranges
• Type casting and integer division
• Arithmetic, relational and logical operators
• Operator precedence
• Reading input with Scanner
• Formatted output with printf

• What is a variable?
• Data types in Java

Making decisions and repeating work with conditions and loops.

• if, else if and else
• switch statements and switch expressions
• for, while and do-while loops
• break and continue
• Nested loops and patterns
• Tracing loops by hand

• if-else: choose one of two paths
• The for loop

Breaking programs into methods and working with arrays and text.

• Defining and calling methods
• Parameters, return values and overloading
• Pass-by-value in Java
• One- and two-dimensional arrays
• Common array algorithms: sum, max, search, reverse
• String methods, immutability and StringBuilder
• == versus equals()

• Define and call a method
• What is an array?
• Search in a String: indexOf, contains, startsWith

The core of object-oriented programming: modelling things as classes with state and behaviour.

• Classes, objects and references
• Fields, methods and constructors
• this and constructor chaining
• Encapsulation with private fields, getters and setters
• static members and final
• toString(), equals() and hashCode()

• What is object-oriented programming?

Reusing and extending code safely, and writing code that works with many types.

• extends and super
• Method overriding and @Override
• Abstract classes
• Interfaces and default methods
• Polymorphism and dynamic dispatch
• Composition versus inheritance
• Enums

• extends: parent and child classes
• Abstract classes and abstract methods

The Java Collections Framework and type-safe generic code.

• Why generics
• List: ArrayList and LinkedList
• Set: HashSet and TreeSet
• Map: HashMap and TreeMap
• Queue and Deque
• Iterating safely and the Iterator
• Sorting with Comparable and Comparator

• Why generics?
• ArrayList: add, get, set, remove
• HashMap: keys and values

Handling errors cleanly and working with files on disk.

• Checked and unchecked exceptions
• try, catch, finally and multi-catch
• try-with-resources
• Throwing and creating your own exceptions
• Reading and writing text files with java.nio.file
• Parsing CSV data

• What is an exception?
• Read a small text file

Functional-style Java and the newer language features used in today's codebases.

• Functional interfaces and lambdas
• Method references
• Stream pipelines: filter, map, sorted, collect
• Collectors: groupingBy and joining
• Optional
• Records, sealed types and pattern matching
• The java.time date and time API

• What is a stream?
• Records as data carriers in streams

Running work in parallel safely: the ideas every Java developer meets.

• Threads and Runnable
• Race conditions and synchronized
• volatile and visibility
• ExecutorService and thread pools
• Concurrent collections
• CompletableFuture at a glance

• What is a thread?

Habits that make your code correct and easy for others to read.

• Using the debugger: breakpoints and stepping
• Unit tests with JUnit 5
• Naming, small methods and clean code
• Version control with Git and GitHub
• Reading stack traces

• Manual testing vs automated testing

Putting it all together in small projects, and where Java can take you next.

• Planning a console project
• Splitting code into classes and packages
• Saving data to files
• Pushing your project to GitHub
• Next steps: DSA, SQL and JDBC, Spring Boot

Covered in 1:1 mentoring sessions