Java practice
0 exercises and 108 quizzes from the lessons of this track. Sample tests run in your browser; what you pass is kept in this browser only.
Start here: JDK 25 LTS and your first programs
- Quiz: What Java is, how it runs and where it is used
- Quiz: Install JDK 25 and choose a JDK build
- Quiz: Your first program: a compact source file
- Quiz: Classic main, javac and .class files
- Quiz: Java versions, LTS and preview features
- Quiz: Reading input with IO.readln and Scanner
- Quiz: JShell: try Java one line at a time
- Quiz: IDEs, compiler errors and your first debug
- Quiz: How Java runs: bytecode, class loading, JIT
Variables, types and operators
- Quiz: Variables and the eight primitive types
- Quiz: Integer arithmetic, division and overflow
- Quiz: Floating point, rounding and BigDecimal
- Quiz: char, boolean, casting and conversions
- Quiz: Operators, precedence and short-circuiting
- Quiz: Bitwise operators, shifts and bit tricks
- Quiz: Strings: first look and equality
- Quiz: Formatted output with printf and formatted
- Quiz: Wrapper classes, autoboxing and caching
- Quiz: Comments, Javadoc and naming conventions
Control flow, methods and recursion
Arrays and strings in depth
- Quiz: Arrays: creation, indexing and iteration
- Quiz: The Arrays class: sort, search, fill, compare
- Quiz: 2D and jagged arrays for grids and matrices
- Quiz: The String API in depth
- Quiz: StringBuilder and string-building performance
- Quiz: Text blocks for multi-line strings
- Quiz: Unicode, UTF-16 and Indian scripts
- Quiz: String hashing, interning and locale traps
Classes, objects, records and enums
- Quiz: Classes, objects, fields and constructors
- Quiz: Growing a compact file into classes and files
- Quiz: Encapsulation and access modifiers
- Quiz: Static members and initialisation order
- Quiz: Packages, imports and the class path
- Quiz: Java equals, hashCode and toString contracts
- Quiz: Immutable classes and defensive copies in Java
- Quiz: Java enums with fields, methods and EnumMap
- Quiz: Java records for immutable data
- Quiz: Java nested, inner, local and anonymous classes
Inheritance, interfaces and polymorphism
- Quiz: Inheritance, super and constructor chaining
- Quiz: Overriding, polymorphism and dynamic dispatch
- Quiz: Abstract classes and template methods
- Quiz: Interfaces: default, static and private methods
- Quiz: Sealed classes and interfaces
- Quiz: Composition over inheritance in Java
- Quiz: Casting, instanceof and type patterns
Lambdas, functional interfaces and Optional
Streams and stream gatherers
Files, I/O and NIO.2
Testing, build tools and code quality
- Quiz: Unit testing with JUnit 6
- Quiz: Parameterised tests, lifecycle and AssertJ
- Quiz: Test doubles, fakes and Mockito
- Quiz: TDD kata: amounts in Indian words
- Quiz: Maven: POM, lifecycle and dependencies
- Quiz: Gradle: Kotlin DSL, toolchains and tasks
- Quiz: Dependency management and supply-chain safety
- Quiz: Code quality: javac lint, javadoc, formatting
- Quiz: Debugging techniques and logging
JVM internals, memory, GC and performance
- Quiz: Class loading and JVM architecture
- Quiz: Reading bytecode with javap
- Quiz: JIT compilation and warm-up
- Quiz: Heap, stack, references and object headers
- Quiz: Garbage collectors: G1, ZGC, Shenandoah
- Quiz: Memory leaks, heap dumps and OOM errors
- Quiz: JDK Flight Recorder and profiling
- Quiz: Microbenchmarks with JMH
- Quiz: Startup: AOT cache and native images
- Quiz: The JVM in containers and key flags
Modules, packaging and distribution
Desktop GUIs with JavaFX (and Swing for legacy code)
- Quiz: JavaFX setup and your first window
- Quiz: JavaFX panes, shapes, colours, fonts and images
- Quiz: JavaFX properties, binding and listeners
- Quiz: JavaFX events: handlers, mouse and keys
- Quiz: JavaFX controls: labels, buttons, text and lists
- Quiz: JavaFX animation, audio and video
- Quiz: JavaFX FXML, controllers, CSS and Scene Builder
Jakarta EE web: Servlets and Tomcat
Jakarta Faces (JSF): component-based web UIs
Jakarta REST (JAX-RS) and CDI: services beyond Faces
Advanced language and platform features
Java for DSA, placements and online assessments
Java in practice: Android, upgrades and certification
Results here are what this browser has checked: feedback for you, not proof. They stay on this device; your Learn progress can be exported to a file. · Back to the Java track