Introduction to Programming by Samoylov, Nick -- Read -- Imperial Library of Trantor

Index

Title Page Copyright and Credits

Introduction to Programming

Dedication Contributors

About the author About the reviewers Packt is searching for authors like you

Packt Upsell

Why subscribe? PacktPub.com

Preface

Who this book is for What this book covers To get the most out of this book

Download the example code files Download the color images Conventions used

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Java Virtual Machine (JVM) on Your Computer

What is Java?

Basic terms History and popularity Principles

Java platforms, editions, versions, and technologies

Platforms and editions Versions Technologies

Java SE Development Kit (JDK) installation and configuration

Where to start The page with Java installers How to install

Main Java commands

The JVM execution command The compilation command Command jcmd and other commands

Exercise – JDK tools and utilities

Answer

Summary

Java Language Basics

The basic terms of Java programming

Byte code Defects (bugs) and their severity and priority Java program dependencies Statements Methods Classes The Main class and the main method

Classes and objects (instances)

Java classes Java object (class instance)

Class (static) and object (instance) members

Private and public Static members Object (instance) members Method overloading

Interface, implementation, and inheritance

Interface Implementation Inheritance The java.lang.Object class

The equals() method The hashCode() method The getClass() method The toString() method The clone() method The wait() and notify() methods

OOP concepts

Object/class Encapsulation Inheritance Interface (abstraction) Polymorphism

Exercise – Interface versus abstract class

Answer

Summary

Your Development Environment Setup

What is the development environment?

Java editor is your main tool Source code compilation Code sharing Code and test execution

Setting the classpath

Manual setting Searching on the classpath IDE sets the classpath automatically

There are many IDEs out there

NetBeans Eclipse IntelliJ IDEA

Installing and configuring IntelliJ IDEA

Downloading and installing Configuring IntelliJ IDEA

Exercise – Installing NetBeans IDE

Answer

Summary

Your First Java Project

What is a project?

Definition and origin of project Project-related terms A project's life cycle

Creating a project

Creating a project using a project wizard Maven project configuration Changing IDE settings at any time

Writing an application code

Java package declaration Creating a package Creating the MyApplication class Building the application Hiding some files and directories Creating the SimpleMath class Creating methods

Executing and unit testing an application

Executing the application using the IDE Creating a unit test Executing the unit test How many unit tests are enough?

Exercise – JUnit @Before and @After annotations

Answer

Summary

Java Language Elements and Types

What are the Java language elements?

Input elements Types

Comments Identifiers and variables

Identifier Variable Variable declaration, definition, and initialization Final variable (constant)

Reserved and restricted keywords

Reserved keywords Restricted keywords

Separators

Semicolon ";" Braces "{}" Parentheses "()" Brackets "[]" Comma "," Period "." Ellipsis "..." Colons "::" At sign "@"

Primitive types and literals

The Boolean type Integral types Floating-point types Default values of primitive types Primitive type literals

Reference types and String

Class types Interface types Arrays Default value of a reference type Reference type literals String immutability Enum types Passing reference type values as method parameters

Exercise – Variable declarations and initializations

Answer

Summary

Interfaces, Classes, and Object Construction

What is an API?

Java APIs Command line APIs HTTP-based APIs Software component API

Interface and object factory as API

Interface Object factory Reading configuration file

Using the json-simple library Using the json-api library Unit test

Calculator API

Adding static methods to API The API is complete

Overloading, overriding, and hiding

Interface method overloading Interface method overriding Interface static member hiding Class member hiding Instance method overriding Instance method overloading

This, super, and constructors

Keyword this and its usage Keyword super and its usage Constructors

Final variable, final method, or final class

Final variable Final method Final class

Exercise – Restricting a class instantiation to a single shared instance

Answer

Summary

Packages and Accessibility (Visibility)

What is importing?

Structure of the .java file and packages Single class import Multiple classes import Static import

Access modifiers

The accessibility of a top-level class or interface Access to class or interface members The constructor's accessibility is the same as any class member

Encapsulation

Data hiding and decoupling Flexibility, maintainability, and refactoring Reusability Testability

Exercise – Shadowing

Answer

Summary

Object-Oriented Design (OOD) Principles

What is the purpose of design?

The project's feasibility Requirement gathering and prototyping High-level design Detailed design Coding Testing

A roadmap to a good design

Encapsulating and coding to an interface Taking advantage of polymorphism Decoupling as much as you can Preferring aggregation over inheritance So many OOD principles and so little time

Exercise – Design patterns

Answer

Summary

Operators, Expressions, and Statements

What are the core elements of Java programming?

Operators

Arithmetic unary (+ -) and binary operators: + - * / % Incrementing and decrementing unary operators: ++ -- Equality operators: == != Relational operators: < > <= >= Logical operators: ! & | Conditional operators: && || ? : (ternary) Assignment operators (most popular): = += -= *= /= %= Instance creation operator: new Type comparison operator: instanceof Preferring polymorphism over the instanceof operator Field access or method invocation operator: . Cast operator: (target type)

Expressions Statements

Operator precedence and evaluation order of operands

Operator precedence Evaluation order of operands

Widening and narrowing reference types

Widening Narrowing

Widening and narrowing conversion of primitive types

Widening Narrowing Methods of primitive type conversion

Boxing and unboxing between primitive and reference types

Boxing Unboxing

Method equals() of reference types

Using the implementation of the base class Object Overriding the equals() method Using the identification implemented in the parent class The equals() method of the String class The equals() method in wrapper classes of primitive types

Exercise – Naming the statements

Answer

Summary

Control Flow Statements

What is a control flow?

Selection statements Iteration statements Branching statements Exception handling statements

Selection statements

if if...else if...else if-...-else switch...case

Iteration statements

while do...while for for enhanced for with multiple initializers and expressions

Branching statements

Break and labeled break Continue and labeled continue return

Exception handling statements

throw try...catch Checked and unchecked (runtime) exceptions throws Custom exceptions What is exception handling? Some best practices of exception handling finally Assert requires JVM option -ea

Exercise – Infinite loop

Answer

Summary

JVM Processes and Garbage Collection

What are JVM processes?

Loading Linking Initialization Instantiation Execution Garbage collection Application termination

JVM architecture

Runtime data areas Classloader Execution engine

Threads

Extending the Thread class What is daemon? Running threads extending Thread Implementing Runnable Runing threads implementing Runnable Extending Thread vs implementing Runnable

How to execute the main(String[]) method

Using IDE Command line with classes on classpath Command line with a .jar file on classpath Command line with an executable .jar file

Garbage collection

Responsiveness, throughput, and stop-the-world Object age and generations When stop-the-world is unavoidable

Exercise – Monitoring JVM while running an application

Answer

Summary

Java Standard and External Libraries

What are standard and external libraries? Java standard libraries

java.lang java.util java.time java.io and java.nio java.sql and javax.sql java.net java.math java.awt, javax.swing, and javafx

Java external libraries

org.junit org.mockito org.apache.log4j and org.slf4j org.apache.commons

org.apache.commons.io org.apache.commons.lang and lang3 org.apache.commons.codec.binary

Exercise – Comparing String.indexOf() and StringUtils.indexOf()

Answer

Summary

Java Collections

What are collections?

The java.util package Apache Commons collections Collections vs arrays Here is what we are going to discuss

List - ArrayList preserves order

Prefer variable type List Why is it called ArrayList? Adding elements size(), isEmpty(), clear() Iterate and stream Add using generics Add collection Implementing equals() and hashCode() Locating element Retrieving elements Removing elements Replacing elements Sorting String and numeral types Sorting custom objects Comparing with another collection Converting to array List implementations

Set - HashSet does not allow duplicates

Preferring variable type Set Why is it called HashSet? Adding elements size(), isEmpty(), and clear() Iterate and stream Adding using generics Adding collection Implementing equals() and hashCode() Locating element Retrieving elements Removing elements Replacing elements Sorting Comparing with another collection Converting to array Set implementations

Map – HashMap stores/retrieves objects by key

Preferring variable type Map Why is it called HashMap? Adding and maybe replace size(), isEmpty(), and clear() Iterate and stream Adding using generics Adding another Map Implementing equals() and hashCode() Locating element Retrieving elements Removing elements Replacing elements Sorting Comparing with another collection Map implementations

Exercise – EnumSet methods

Answer

Summary

Managing Collections and Arrays

Managing collections

Initializing collections

Collection constructor Instance initializer (double brace) Static initialization block Factory methods of() Using other objects and streams

Immutable collections

Immutable versus unmodifiable Immutable without methods of() Methods add() and put() confusion

java.util.Collections class

Copy Sort and equals() Reverse and rotate Search and equals() Comparing two collections Min and max elements Add and replace elements Shuffle and swap elements Converting to a checked collection Convert to a thread-safe collection Convert to another collection type Create enumeration and iterator

Class collections4.CollectionUtils

Manage arrays

Initialize arrays

Creation expression Array initializer Static initialization block From collection Other possible methods

Class java.util.Arrays Class lang3.ArrayUtils

Exercise – Sort list of objects

Answer

Summary

Managing Objects, Strings, Time, and Random Numbers

Managing objects

Class java.util.Objects

equals() and deepEquals() hash() and hashCode() isNull() and nonNull() requireNonNull() checkIndex() compare() toString()

Class lang3.ObjectUtils

Managing strings

StringBuilder and StringBuffer Class java.lang.String

Constructors format() replace() compareTo() valueOf(Objectj) valueOf(primitive or char[]) copyValueOf(char[]) indexOf() and substring() contains() and matches() split(), concat(), and join() startsWith() and endsWith() equals() and equalsIgnoreCase() contentEquals() and copyValueOf() length(), isEmpty(), and hashCode() trim(), toLowerCase(), and toUpperCase() getBytes(), getChars(), and toCharArray() Get code point by index or stream

Class lang3.StringUtils

Managing time

java.time.LocalDate java.time.LocalTime java.time.LocalDateTime Period and Duration

Managing random numbers

Method java.lang.Math.random() Class java.util.Random

Exercise – Objects.equals() result

Answer

Summary

Database Programming

What is Java Database Connectivity (JDBC)?

Connecting to the database Closing the database connection Structured Query Language (SQL)

Creating a database and its structure

CREATE and DROP the database and its user CREATE, ALTER, and DROP table

Create, read, update, and delete (CRUD) data

INSERT statement SELECT-statement UPDATE-statement DELETE-statement Using the PreparedStatement class

Exercise – Selecting unique first names

Answer

Summary

Lambda Expressions and Functional Programming

Functional programming

What is a functional interface? Ready-to-use standard functional interfaces

Function<T, R> Consumer<T> Supplier<T> Predicate<T> Other standard functional interfaces

Chaining standard functions

Chain two Function<T,R> Chain two Consumer<T> Chain two Predicate<T> identity() and other default methods

Lambda expressions

What is a lambda expression? Re-implementing functions Lambda limitations

Effectively final local variable The this keyword interpretation

Method references

Exercise – Using the method reference to create a new object

Answer

Summary

Streams and Pipelines

What is a stream?

Stream operations

Creating a stream

Stream interface

empty(), of(T t), ofNullable(T t) iterate(Object, UnaryOperator) concat(Stream a, Stream b) generate(Supplier) of(T... values)

The Stream.Builder interface Other classes and interfaces

Intermediate operations

Filtering Mapping Sorting Peeking

Terminal operations

Processing each element Counting all elements Matching all, any, or none Finding any or first

Class Optional

Min and max The toArray() operation The reduce operation The collect operation

Class collectors

Numeric stream interfaces

Creating a stream

range(), rangeClosed()

Intermediate operations

boxed() and mapToObj() mapToInt(), mapToLong(), and mapToDouble() flatMapToInt(), flatMapToLong(), and flatMapToDouble()

Terminal operations

sum() and average()

Parallel processing

Stateless and stateful operations Sequential or parallel processing?

Exercise – Multiplying all the stream elements

Answer

Summary

Reactive Systems

How to process a lot of data quickly

Asynchronous

Sequential versus parallel streams Using the CompletableFuture class

Non-blocking

The java.io versus java.nio package Event loop, or run loop

Distributed Scalable Reactive

Responsive Resilient Elastic Message-driven

Microservices

Vert.x basics The HTTP server as a microservice Periodic service as a microservice The HTTP client as a microservice Other microservices

Reactive systems

Message-driven system

Message consumer Message sender Message publisher

Reality check

Exercise – Creating io.reactivex.Observable

Answer

Summary

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