Java Challengers: Master the Java Fundamentals with fun Java Code Challenges! Become a Java Challenger!

Table of Contents
1 Introduction
	1.2 Why Java?
	1.3 What kinds of concepts are in this book?
	1.4 Who is this book for?
	1.5 What are the Java Challenges?
	1.6 Disclaimer about the Java Challenges
	1.7 Java versioning and tools
	1.8 Will this book prepare you for the software development market?
2 Variable types and flow control (Review)
	2.1 A Brief Review about Algorithms
	2.2 Arithmetic Operators
	2.3 Flow Control
	2.4 Loops
	2.5 Arrays
	2.6 Local variable restrictions
	2.7 Candy Price Code Challenge
	2.8 Summary
3 Basic object-oriented programming (Review)
	3.1 Classes
	3.2 Methods
	3.3 The Keyword this
	3.4 Constructors
	3.5 Object references
	3.6 Arrays are objects in Java
	3.7 Bank Deposit/Withdraw Challenge
	3.8 Summary
4 Encapsulation access modifiers, and package structure
	4.1 Programming to interfaces
	4.2 What are and how to use getters and setters?
	4.3 The Builder Design Pattern
	4.4 Organizing Packages in a Real Project
	4.5 Encapsulation Patterns
	4.6 Access Modifiers
	4.7 Inner Class
	4.8 The static keyword
	4.9 Instance and static block
	4.10 Small Real-World Project Challenge
	4.11 Summary
5 Overloading
	5.1 Overloading basics
	5.2 Wrappers and autoboxing
	5.3 Varargs
	5.4 Overloading Real-World Usage Challenge
	5.5 Summary
6 Inheritance and Polymorphism
	6.1 When to use inheritance
	6.2 Every Class is an Object
	6.3 Checking the type of an object
	6.4 The toString method
	6.5 Access modifiers and inheritance
	6.6 Object composition
	6.7 Multiple inheritance in Java
	6.8 Using super to access a parent class’s methods
	6.9 Constructors and inheritance
	6.10 Class casting
	6.11 Preventing inheritance
	6.12 Abstract classes
	6.13 Factory Method Strategy Discount Real-world Challenge
	6.14 Summary
7 Interfaces
	7.1 Interfaces and Polymorphism
	7.2 Covariant return types
	7.3 Default methods
	7.4 Abstract classes vs. interfaces
	7.5 Static methods in interfaces
	7.6 Simulating multiple inheritance with default methods
	7.7 Private methods in interfaces
	7.8 Command Design Pattern Challenge
	7.9 Summary
8 Exceptions
	8.1 Checked and unchecked exceptions
	8.2 Stack Trace
	8.3 Handling or Declaring Checked Exceptions
	8.4 try, catch, finally
	8.6 try with resources
	8.7 Multi catch
	8.8 Creating a customized exception
	8.9 Throw early, catch late
	8.10 Real World Exception Creation Challenge
	8.11 Summary
9 Lambdas and Functional Interfaces
	9.1 What is Lambda?
	9.1.3 Mysterious Door Lambda Challenge
	9.2 Functional Interfaces
	9.3 Method Reference
	9.4 Lambda Method Reference Matcher Challenge:
	9.5 Summary
10 Optional
	10.1 Wrapping a value into Optional
	10.2 isPresent and isEmpty
	10.3 Optional Antipatterns
	10.4 ifPresent and ifPresentOrElse
	10.6 Handling Exceptions with orElseThrow
	10.7 Transforming Optional Data
	10.8 Final Yoshi Food Optional Challenge
	10.9 Summary
11 Generics and Object Comparison
	11.1 Comparing objects with equals and hashcode
	11.2 Generics
	11.4 Upper and Lower Bound Generics
	11.5 Summary
12 Collections
	12.1 Collections API
	12.2 List
	12.3 ArrayList
	12.4 Vector
	12.5 Deque & Stack
	12.6 ConcurrentModificationException
	12.7 Using Comparable
	12.8 Set
	12.9 HashSet
	12.10 LinkedHashSet
	12.11 TreeSet
	12.12 Map
	12.16 TreeMap
	12.17 Elements Searching
	12.18 Summary
13 Streams
	Creating a Stream
	Intermediate Operations
	Terminal Operations
	Transforming Streams
	Processing Order
	Parallel Stream
	Summary
13 Newest Features of Java (In Development)
	13.1 Introduction to Modules Java 9
	13.2 Reserved word var from Java 10
	13.3 New switch case statement from Java 14
	13.4 Using record from Java 14
	13.5 Using Sealed classes Java 15
	13.6 Using Pattern Matching Type Checks Java 15
	13.7 Text Blocks Java 15
	13.8 Summary