Support formation vidéo : OCA Java SE 8 Programmer (1Z0-808) (1)

Formation OCA Java Se 8 Programmer (1Z0-808)
Formation OCA, Java Se 8 Programmer 1Z0-808
Préparée par:
Anis HACHANI
Formateur et consultant en IT
Certifié OCJP, RHCE 6&7, LPI-3, OCE, OCA, OCP
Comptia Sec+, Agile ( PSM )

Présentation générale
Le programme de certification Java est offert par Oracle, actuellement la plupart des entreprises préfèrent embaucher des
personnes qui ont une certification.
Une certification Java prouve qu'une personne est compétent dans la technologie Java et possède les compétences
requises définit nécessaires pour effectuer une tâche spécifique
Avoir une certification permet d’ouvrir plusieurs opportunités à savoir :
Cursus du développeur mobile ( Android )
Cursus du développeur web ( JEE , Spring framework ..)
Cursus développeur Java Desktop Application
En plus == > Avoir la certification, ça implique la maitrise du concept de l’orienté objet
 Python, Php, Ruby, Objective C, Swift, …

Présentation générale
Formation OCA Java Se 8 Programmer I 1Z0-808

Présentation formateur
Anis Hachani
Contact : contact@ghazelatc.com
Mon profil LinkedIn : https://www.linkedin.com/in/anis-hachani-546bb13a/
Formateur ,Chef de projet et consultant en IT
Fondateur de Ghazela Technology Academy :
Formation et consulting en Technology, Management et en Digital
Sous-traitance de projets informatique
Je dispense des formations en IT depuis plus de 6 ans.

Plan formation
Chapitre 1 : Initiation orienté objet (class, objet, instance, variable ..)
Java Building Blocks
Chapitre 2 : Opérateurs et structures conditionnelles ( > =, if, else)
Operators and Statments
Chapitre 3 : Librairie native de java, (API Java )
Core Java APIs
Chapitre 4 : Méthode et encapsulation
Methodes and Encapsultion
Chapitre 5 : Héritage, Polymorphisme , Interface, classes abstraites
Class Design
Chapitre 6 : Les Exceptions, les classe imbriquées, les classes
anonymes, Lambda
Exceptions, Inner class, Anonymous class, Lambda

Prérequis
Avoir suivi la formation Programmation Orientée Objet en Java ou avoir les
connaissances équivalentes
Avoir une bonne pratique du langage Java sur au moins un projet.

Public concerné
Développeur Java
Chef de projet
Développeur ayant codé avec un autre langage de programmation orienté
objet

Objectifs visés
Réussir la certification " Oracle Certified Associate, Java SE 8 Programmer I ,OCJA 8
, 1Z0-808

Environnement de travail
Machine : Windows XP/7/8/8.1/10.. | Linux ou Unix
Outils : Bloc note , note pad ++
IDE : Netbeans | Eclipse| autre IDE
Programme à télécharger : JDK 1.8

Liens des ressources logicielles
Note pad ++ : https://notepad-plus-plus.org/download/v7.3.3.html
Netbeans : https://netbeans.org/downloads/
JDK 1.8 : http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-
2133151.html
Lien dans le site officiel : https://education.oracle.com/pls/web_prod-plq-
dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-808

Aperçu sur l’examen OCJA – 1Z0-808
La langue de l’examen
est aux choix :
Français, Anglais …
Lien dans le site officiel :
https://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-808

Support de cours

Formation OCA Java Se 8 Programmer (1Z0-808) 13
Chapitre 1 : Initiation orienté objet (class, objet, instance, variable ..) ~ Java Building Blocks

Révision : Généralités…
• Un peu plus qu’un langage de programmation:
• “gratuit”!
• Indépendant de la plateforme
• Langage interprété et byte code
• Portable
• Syntaxe à la C
• Orienté objet (classes héritage)
• Nombreuses bibliothèques
• Pas de pointeurs! (ou que des pointeurs!)
• Ramasse-miettes

Plateforme Java
• La compilation génère un .class en bytecode (langage intermédiaire indépendant de la plateforme).
• Le bytecode est interprété par un interpréteur Java JVM
• Java Virtual Machine
Compilation javac
interprétation java

• Indépendance de la plateforme

Plateforme Java : plateforme indépendant de l’OS
• La plateforme java: software au-dessus d’une plateforme exécutable sur un hardware
(exemple MacOs, linux …)
• Java VM
• Java application Programming Interface (Java API):

Java ,tout un environnement…
• JDK: Java Developpement Kit
• JRE : Java Runtime Environment
• Java compiler,Java Debugger
• RMI ,Awt , Swing, Internal and external API(Application programmable interface )
• IDE ( eclipse ,Netbeans, jdeveloper )

Utilisation du langage Java pour développer:
• Une application avec interface graphique
• Une application Android
• Java Enterprise Edition JEE6,7,8..,etc..

1- Téléchargement et installation du JDK 1.8
2- Configuration de la variable d'environnement
JAVA_HOME
3- Compilation et exécution d’une class java
4- Téléchargement Installation Netbeans
Exercice

test.java
1 - Créer le fichier test.java sous c:/java
2 – Compiler en byte code le fichier test.java avec la commande Javac
javac test.java
3 – java test
public class test {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
System.out.println("hello");
}
}

Principes de base de la Programmation orientée objet
Classe : Représente le modèle
Une classe a des champs nommé attribut
Une classe a des fonction appelé méthodes
L’appel d’une classe est appelé instanciation ,le résultat de
Cet appel est appelé un objet
Exemple:
Voiture a un vitesse x , un prix y, un modèle z
La voiture roule: ( action)

Implémentation de la classe voiture

Les identifiants légaux ( Legal Identiﬁers )
1 . Identifiers must start with a letter, a currency character ($), or a
Connecting character such as the underscore ( _ ).
Identifiers cannot start with a number!
After the first character, identifiers can contain any combination of letters,
currency characters, connecting characters, or numbers.
Enum Identifiers in Java are case-sensitive;
foo and COLLIE ,collie are two different identifiers.

On ne peut pas utiliser le mot Java comme identifiant an identifier.

General code best practice ( Les bonnes pratique de coding en Java )
Classes and interfaces The first letter should be capitalized:
Example for classes: Dog
Account
PrintWriter
Example for interfaces : Runnable
Serializable
Example for methodes : getBalance
get/set/is doCalculation
setCustomerName
Variables (miniscule): buttonWidth
accountBalance
Constants (majuscule) ex :static, final : MIN_HEIGHT

Une seule classe public dans un fichier .java
1 - There can be only one public class per source code file.
2 - A file can have more than one nonpublic class.

Access modifiers ( Les Modificateurs d'accès )
class MyClass { }
Access modifiers: public, protected, private, package (par défaut )
Variable , méthode & classe
Class :
Public : La classe est accessible pour toute les classes du projet
Package: La classe est accessible par toute les classes du même package
Protected /private pas de sens
Ordre de visibilité : Classe, méthode, variable

Visibilité

Visibilité
Private < package < Protected < Public

If there is a public class in a file, the name of the file must match the name
of the public class. For example, a class declared as public class Dog { }
must be in a source code file named Dog.java.
Les bonnes pratiques de coding ( Coding est practice )

Import de la classe Beverage

Commentaire // Comments
// comment until end of line
/* Multiple
* line comment
*/
Raccourcit : ctrl + alt+ c

Import des classes // Class imports

import des classes // Concept package :

Concept package : import des classes

Constructor Declarations ( la déclaration des contructeurs )
In Java, objects are constructed. Every time you make a new object, at least one
constructor is invoked. Every class has a constructor, although if you don't create
one explicitly, the compiler will build one for you. There are tons of rules concerning

Block d’initialisation // Instance Initializer Blocks

Lab : initialization bloc (Block d’initialisation )

Lab : initialization bloc
Resultat : 5

Les identifiants / / Identifiers

Apprendre les valeurs par défaut des variables
Understanding Default Initialization of Variables

Le scope de la variable // Variables scope

Le ramasse miette // Garbage Collection

Remember, finalize() is only run when the object is eligible for garbage collection.

Exercice du premier chapitre
Chapter 1 questions
Chapitre 1 : Java Building Blocks

Liste des exercices
Page 42
OCA Oracle
Certified Associate
Java SE 8 Programmer I
Study Guide Exam 1Z0-808

Chapitre 2 : Opérateurs et structures conditionnelles ( > =, if, else) ~ Operators and Statments

Default litervals for int, long ,float , double
Les valeurs par défault pour int, long , float, double
byte < short < int < long : entier
float < double : réel
Toute valeur entier est considéré comme un int
Toute valeur réel est considéré comme un double

Comprendre les operateurs java
Understanding Java Operators
int y = 4;
double x = 3 + 2 * --y;
Result of x

Arithmetic Operators
Les operateurs arithmétique
int x = 2 * 5 + 3 * 4 - 8;

Arithmetic operators are often encountered in early mathematics and include addition
(+), subtraction (-), multiplication (*), division (/), and modulus (%). They also include the
As you may have noticed in Table 2.1, the multiplicative operators (*, /, %) have a higher order of
precedence
than the additive operators (+, -). That means when you see an expression such as this:
int x = 2 * 5 + 3 * 4 - 8;
You first evaluate the 2 * 5 and 3 * 4, which reduces the expression to the following:
int x = 10 + 12 - 8;
Then, you evaluate the remaining terms in left-to-right order, resulting in a value of x of 14.
Arithmetic Operators
Les operateurs arithmétique

int x = 2 * ((5 + 3) * 4 – 8);

Notice that we said “Unless overridden with parentheses…”.
That’s because you can change the order of operation explicitly by wrapping parentheses around the sections
you want evaluated first. Compare the previous example with the following
one containing the same values and operators, in the same order, but with two sets of
parentheses:
int x = 2 * ((5 + 3) * 4 – 8);
This time you would evaluate the addition operator 10 + 3, which reduces the expression
to the following:
int x = 2 * (8 * 4 – 8);
You can further reduce this expression by multiplying the first two values within the
parentheses:
int x = 2 * (32 – 8);
Next, you subtract the values within the parentheses before applying terms outside the
parentheses:
int x = 2 * 24;

System.out.print(9 / 3);
System.out.print(9 % 3);

Numeric Promotion Rules ( Règles de promotion numérique )
1. If two values have different data types, Java will automatically promote one of the values to the larger of the two data types
Si on a deux valeurs de type de donnée différent, java va automatiquement adapter un des deux valeurs vers le type de
donnée le plus large.
.
2. If one of the values is integral and the other is floating-point, Java will automatically promote the integral value to the floating-
point value’s data type.
Si on deux valeurs, le premier est de type entier, le deuxième est de type réel , Java va adapter automatiquement la valeur
de type entier en une valeur de type réel
3. Smaller data types, namely byte, short, and char, are first promoted to int any time they’re used with a Java binary arithmetic
operator, even if neither of the operands is int.
Les données les plus petit à savoir byte, short, and char, vont etre adapter avec les opérations arithmétique vers le type de
donnée entier meme si aucun des deux valeurs est de type entier
4. After all promotion has occurred and the operands have the same data type, the resulting value will have the same data type as its
promoted operands.
- Le type de donnée de la valeur du résultat va s’adapter au des deux type de donnée de l’opération
Chapitre 2 : Operators and Statements

What is the data type of x * y?
int x = 1;
long y = 33;
What is the data type of x + y?
double x = 39.21;
float y = 2.1;
Numeric Promotion Rules
Règles de promotion numérique

What is the data type of x * y?
int x = 1;
long y = 33;
If we follow the first rule, since one of the values is long and the other is int, and long
is larger than int, then the int value is promoted to a long, and the resulting value is long.
What is the data type of x + y?
double x = 39.21;
float y = 2.1;
This is actually a trick question, as this code will not compile! As you may remember
from Chapter 1, floating-point literals are assumed to be double, unless post fixed with an f, as in 2.1f. If the value
was set properly to 2.1f, then the promotion would be similar to the last example, with both operands being
promoted to a double, and the result would be a double value.

What is the data type of x / y?
short x = 10;
short y = 3;
What is the data type of x * y / z?
short x = 14;
float y = 13;
double z = 30;

What is the data type of x / y?
short x = 10;
short y = 3;
In this case, we must apply the third rule, namely that x and y will both be promoted
to int before the operation, resulting in an output of type int. Pay close attention to
the fact that the resulting output is not a short, as we’ll come back to this example in
the upcoming section on assignment operators.
¦
What is the data type of x * y / z?
short x = 14;
float y = 13;
double z = 30;
In this case, we must apply all of the rules. First, x will automatically be promoted to int solely because it is a short
and it is being used in an arithmetic binary operation.
The promoted x value will then be automatically promoted to a float so that it can be
multiplied with y. The result of x * y will then be automatically promoted to a double,
so that it can be multiplied with z, resulting in a double value.

Les opérateurs unaire

The logical complement operator ! ( l’opérateur logique complémentaire ! )
boolean x = false;
System.out.println(x);
x = !x;
Likewise, the negation operator, -, reverses the sign of a numeric expression, as shown in these statements:
System.out.println(x); // 1.21
x = -x;
System.out.println(x); // -1.21
x = -x;
System.out.println(x); // 1.21

int x = !5;
boolean y = -true
boolean z = !0;
Will this run ?

The following code snippet illustrates this distinction:
int counter = 0;
System.out.println(counter); // Outputs 0
System.out.println(++counter); // Outputs 1
System.out.println(counter--); // Outputs 1
The first pre-increment operator updates the value for counter and outputs the new
value of 1. The next post-decrement operator also updates the value of counter but outputs
the value before the decrement occurs.
One common practice in a certification exam, is to apply multiple increment or decrement operators to a single
variable on the same line:
int x = 3;
int y = ++x * 5 / x-- + --x;
System.out.println("x is " + x);
System.out.println("y is " + y);
Increment and Decrement Operators
Les opérateurs d’incrementation et de décrementation

Les opérateurs d’incrémentation et de décrémentation
int x = 3;
int y = ++x * 5 / x-- + --x;
System.out.println("x is " + x);
System.out.println("y is " + y);
So how do you read this code? First, the x is incremented and returned to the expression,
which is multiplied by 5. We can simplify this:
int y = 4 * 5 / x-- + --x; // x assigned value of 4
Next, x is decremented, but the original value of 4 is used in the expression, leading to
this:
int y = 4 * 5 / 4 + --x; // x assigned value of 3
The assignment of x reduces the value to 2, and since this is a pre-increment operator,
that value is returned to the expression:
int y = 4 * 5 / 4 + 2; // x assigned value of 2
Finally, we evaluate the multiple and division from left-to-right, and finish with the addition.
The result is then printed:
x is 2
y is 7

Int x = 5
System.out.println( ++x + x + x++ + x + x + x++ );

Int x = 5
++ x : pre-incrementation ( pre-increment operator ) :
L’operateur d’incrementation est appliqué et la nouvelle valeur de x est mis à jour
x++ : post-incrementation ( post-increment operator ):
La valeur d’origine de x est affichée et l’operateur d’incrementation est appliqué au prochain
traitement ou affichage .

Les operateurs d’affectation (Assignment Operators )

Casting des types primitive

short x = 10;
short y = 3;
short z = x * y;
Will this compile

short x = 10;
short y = 3;
short z = (short)(x * y);
short values are automatically promoted to int when applying any arithmetic operator,
with the resulting value being of type int. Trying to set a short variable to an int results in a
compiler error, as Java thinks you are trying to implicitly convert from a larger data type to
a smaller one.

Compound Assignment Operators ( Les opérateurs d’affectation composées )

Relational Operators ( les opérateurs relationnel )

Logical Operators (Les opérateurs logiques)

Logical operators
Les opérateurs logique

int x = 6;
boolean y = (x >= 6) || (++x <= 7);
Logical operators

int x = 6;
boolean y = (x >= 6) || (++x <= 7);
Because x >= 6 is true, the increment operator on the right-hand side of the expression
is never evaluated, so the output is 6.
Logical operators

Equality Operators ( Opérateurs d'égalité )

Understanding Java Statements

Ternary Operator
Opérateur Ternaire

int y = 1;
int z = 1;
final int x = y<10 ? y++ : z++;
System.out.println(y+","+z);
Ternary Operator
Opérateur Ternaire

int y = 1;
int z = 1;
final int x = y<10 ? y++ : z++;
// Outputs 2,1
Notice that since the left-hand boolean expression was true, only y was
incremented.
Contrast the preceding example with the following modiﬁ cation
Ternary Operator
Opérateur Ternaire

int y = 1;
int z = 1;
final int x = y>=10 ? y++ : z++;
Ternary Operator
Opérateur Ternaire

int y = 1;
int z = 1;
final int x = y>=10 ? y++ : z++;
// Outputs 1,2
Ternary Operator
Opérateur Ternaire

Switch case

While and do
• while
• ++ expression of a while loop must be declared before the expression is evaluated
 illegal: while (boolean x = true) {}
• The expression result must be a boolean
• do

While
int x = 2;
int y = 5;
while(x < 10)
y++; ?
Boucle infinie

Do , While
int x = 0;
do {
x++;
}
while(false);

Do , While
int x = 0;
do {
x++;
}
while(false);
// Outputs 1

Do , While

Will this compile
for(int i = 0; i < 10; i++) {
System.out.print(i + " ");
}
Will this compile
for( ; ; ) {
System.out.println("Hello World");
}
?

Adding Multiple Terms to the for Statement
int x = 0;
for( long y = 0, z = 4; x < 5 && y < 10; x++, y++)
{
System.out.print(y + " ");
}
System.out.print(x);

int x = 0;
for(long y = 0, x = 4; x < 5 && y < 10; x++, y++) {
System.out.print(x + " ");
}
What do you think

We can fix this loop by changing the declaration of x and y as follows:
int x = 0;
long y = 10;
for(y = 0, x = 4; x < 5 && y < 10; x++, y++) {
}

for(long y = 0, int x = 4; x < 5 && y<10; x++, y++) {
}
What do yo think ?
Declaring long y and int x
Déclaration de long y et de int x

Using Loop Variables Outside the Loop
Utlisation d’une variable déclaré dans une boucle à l’exterieur du boucle
for(long y = 0, x = 4; x < 5 && y < 10; x++, y++) {
System.out.print(y + " ");
}
System.out.print(x);
What do you think

Enhanced loop ~ boucle for amélioré

Nested Loops ( les boucles imbriquées )

Nested loops can include while and do-while, as shown in this example.
See if you can
determine what this code will output.
int x = 20;
while(x>0) {
do {
x -= 2
} while (x>5);
x--;
System.out.print(x+"t");
}
Nested Loops ( les boucles imbriquées )

Optional labels ( les labels optionnelles )

break statement transfers the fow of control out to the enclosing statement , Break with a label
break transfer le control de flux à l’extérieur du bloc d’instruction actuel , Break avec un label

Optional labels ( les labels optionnelles )
break statement transfers the fow of control out to the enclosing statement , Break with a label
break transfer le control de flux à l’extérieur du bloc d’instruction actuel , Break avec un label

Let’s now complete our discussion of advanced loop control with the continue statement, astatement that
causes how to finish the execution of the current loop ( current interation ),

break permet de transférer le control à l'extérieur du bloc
d’intruction actuel, continue permet de d’arreter le
traitement actuel and passer à la prochaine intération

continue with a label
continue without a label
continue avec un label
continues sans label

break with a label
Break avec un label

Exam questions

Liste des exercices
Page 94
OCA Oracle
Certified Associate
Java SE 8 Programmer I
Study Guide Exam 1Z0-808

Chapitre 3 : Librairie native de java, (API Java ) ~ Core Java APIs

What’s the output
int three = 3;
String four = "4";
System.out.println(1 + 2 + three + four);

++ Strings Are Immutable Objects
Once a String object is created, it is not allowed to change. It cannot be made larger or
smaller, and you cannot change one of the characters inside it.
Le moment ou l’objet string est crée, il est pas possible de le changer.
Apercu sur la mémoire

String name = "Fluffy";
name = "anis";
System.out.println(name);
What’s the output

name = "anis";
== >
name = new String(" anis ")

String Class methodes – page 105
Les méthodes de la classe String

Which one compiles ?

String Object is length()
For tables it is length

The StringBuffer and StringBuilder Classes
The java.lang.StringBuffer and java.lang.StringBuilder classes should be used when you have to make a lot of
modifications to strings of characters
As we discussed in the previous section, String objects are immutable, so if you choose to do a lot of
manipulations with String objects, you will end up with a lot of abandoned String objects in the String pool
(waste precious memory )
objects of type StringBuffer and StringBuilder can be modified over and over again without leaving behind a
great effluence of discarded String objects
Oracle recommends that you use StringBuilder instead of StringBuffer whenever possible because
StringBuilder will run faster (and perhaps jump higher).
anything we say about StringBuilder's methods holds true for StringBuffer's methods .

We got a nice new String out of the deal, but the downside is that the old String
abc" has been lost in the String pool, thus wasting memory. If we were using a
StringBuffer instead of a String, the code would look like this:

Example of some methodes of the StringBuilder Classes - Page 114
Exemple des méthodes de la classe StringBuilder - Page 114

Understanding Equality
Comprendre l’égalité

Understanding Equality ( with reference or with equals methode
Comprendre l’égalité ( avec la référence ou par la méthode equals )

Understanding Java Arrays

int[] numbers2 = {42, 55, 99};
Finally, you can type the [] before or after the name, and
adding a space is optional.
This means that all four of these statements do the exact same
thing:
int[] numAnimals;
int [] numAnimals2;
int numAnimals3[];
int numAnimals4 [];

Array Declarations ~ déclaration d’un tableau
In Java, arrays are objects that store multiple variables of the same type,
or variables that are all subclasses of the same type.
Arrays can hold either primitives or object
We can also declare multidimensional arrays, which are in fact arrays of arrays.
This can be done in the following manner:
String[][][] occupantName;
String[] managerName [];

Exemple, pour allouer une matrice de 5 lignes de 6 colonnes
Int [ ] [ ] matrice = new int [5] [6]
Une autre manière :
int[][] matrice = {
{ 0, 1, 4, 3 } , // tableau [0] de int
{ 5, 7, 9, 11, 13, 15, 17 } // tableau [1] de int };
int i, j; for(i=0; i<matrice.length; i++)
{ for(j=0; j<matrice[i].length; j++)
{ //Action sur matrice[i][j] } }
Array Declarations ~ déclaration d’un tableau

• Public String toString()
• Returns a "text representation" of the object.
• Can override to explain the class.
• void finalize()
• Called by garbage collector when the garbage collector sees that the object cannot be referenced.
• final void notify()
• Wakes up a thread that is waiting for this object's lock.
• final void notifyAll ()
• Wakes up all threads that are waiting for this object's lock.
• final void wait()
• Pauses the current thread to wait until another thread calls notify() or notifyAll() on this subject.
Object class methods ~ les méthodes de la class Object

when we don’t override toString ~ lorsque qu’on redéfinit pas la méthode ToString()
Hashcode : objectid

when we override toString ~ lorsqu’on redéfinit pas la méthode ToString()

What about this ?
String[] birds = new String[6];
System.out.println(birds.length);
Using an Array ~ utilisation d’un tableau

Sorting ~ le Tri
import java.util.* // import whole package including Arrays
import java.util.Arrays; // import just Arrays
The result is ?

Trying this again with String types // Essaie du tri avec les types String :
String[] strings = { "10", "9", "100" };
Arrays.sort(strings);
for (String string : strings)
System.out.print(string + " ");
What’s the output
Theproblem is that String sorts in alphabetic order, and 1 sorts before 9.
(Numbers sort before letters and uppercase sorts before lowercase, in case you
were wondering.)

Creating a multidimensionnal Array // creation d’un tableau à deux dimension

Searching // la recherche

Varagrs // argument variable

Methods with variable argument Lists ( vars-args)
Méthodes avec des arguments variable ( vars-args

Understanding an ArrayList
Comprendre les ArrayList

Creating an ArrayList
La creation d’un ArrayList

the new and improved way. Java 5 introduced generics, which allow you to
specify the type of class that the ArrayList will contain.
Java 5 a introduit les generics qui vont permettre de spécifier le type de
donnée d’une liste
ArrayList <String> list4 = new ArrayList<String>();
ArrayList <String> list5 = new ArrayList<>();

Add method // la méthode Add

remove method // la méthode remove

set method // la méthode set

isEmpty() and size() method // la méthode Add isEmpty() et size()

clear method // la méthode clear

contains method // la méthode contains

equals method // la méthode equals

Converting between array and List
La conversion entre un tableau ( array) et une liste

Sorting // le tri

The wrapper classes in the Java API serve two primary purposes:
Up to now, we’ve only put String objects in the ArrayList. What happens if we want to put primitives in?
Each primitive type has a wrapper class, which is an object type that
There is a wrapper class for every primitive in Java. For instance, the wrapper
class for int is Integer, the class for float is Float, and so on. Remember that
the primitive name is simply the lowercase name of the wrapper except for char,
which maps to Character, and int, which maps to Integer. Table 3-2 lists the
wrapper classes in the Java API.

Declaration of a Wrapper Object
La déclaration d’un Wrapper Object

183
When you need to convert the value of a wrapped numeric to a primitive, use one of
the many xxxValue() methods
 primitive xxxValue()
◦ to convert a Wrapper to a primitive: int x = xxWrapper.intValue();
Wrapper Conversion Utilities
les outils de conversion des Wrapper class

184
Declaration of a Wrapper Object
La déclaration d’un Wrapper Object

Wrapper coversion table ,page 243
Table de conversion des Wrapper

Wrapper are immutable

Y++

The API developers decided that for all the wrapper classes, two
objects are equal if they are of the same type and have the same value. It shouldn't be surprising that
== check if the object is same, equals() check the value
Autoboxing

== check if the object is same, equals() check the value
Autoboxing

Example of Boxing
Exemple d’utilisation du Boxing

Conversion between Array and List
Conversion entre Arrays et List

Working with Dates and Times
Utilisaiton du Dates et Times

Manipulation Dates and Times
Utilisation du Dates et Times

Working with Periods
Utilisation des Periode

Formatting Date and Time
Personnalisé la date et le temp

Parsing Date and Time
Parcourir la date et le temp

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