02 basic java programming and operators

Module 02 – Basic Java Programming
Danairat T.
Line ID: Danairat
FB: Danairat Thanabodithammachari
+668-1559-1446

Fundamental Java Programming
The Course Outline
Module 01 – Introduction to Java
Module 02 – Basic Java Programming
Module 03 – Control Flow and Exception Handling
Module 04 – Object Oriented in Java
Module 05 – Java Package and Access Control
Module 06 – Java File IO
Module 07 – Java Networking
Module 08 – Java Threading

Module 02 – Basic Java Programming and Operators
• Basic Java Programming
• Deploying Java Application
• Building Java Archive File
• Executing Basic Java Application
• Monitoring Basic Java Application
• Java Operators

Java File (ASCII Source Code) and Class File (Binary)
In the Java programming language, all source code is first
written in plain text files ending with the .java extension.
Those source files are then compiled into .class file
(bytecode) by the javac compiler.
The java launcher tool then runs your application with an
instance of the Java Virtual Machine.

JVM (Java Virtual Machine)
Because the Java VM is available on many different operating
systems, the same .class files are capable of running on Microsoft
Windows OS, the Solaris Operating System, Linux, or Mac OS.

The Java Platform
The Java platform has two components:
• The Java Virtual Machine
• The Java Application Programming Interface (API)
The API is a large collection of ready-made software components that provide many
useful capabilities. It is grouped into libraries of related classes and interfaces; these
libraries are known as packages.

A Closer Look at the "Hello World!" Application
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello World");
}
}
Class Definition The main Method
The System class from the core library to print the "Hello World!"
message to standard output. System class contains member called
“static PrintStream out” to use as a "standard" output stream.

LAB – Building your first Application with JDeveloper
1.) Click “New Application ” from Jdeveloper 2.) Enter your “Application Name”,
Select “Application Template”, Click ”Next”

3.) (Optional) Enter “Application Package
Prefix”
to organize the structure of Java class files.
4.) Click “Finish”

5.) Right Click “New ” from the Project 6.) Select “Java Class”, Click “OK”

7.) Enter “Name” of the class,
Check “Main Method”
8.) Click “OK”

9.) Write codes in the main method
System.out.println(“Hello World”);
10.) Click “Run” button.

11.) See the result from the console output 12.) (Optional) Review the folder structure
for java source code file

13.) (Optional) Review the file output and Application Directory Structure

Deploying Java Application to execute outside the
IDE with jar command line
Java provides a capability to export your class files into a
single cross platform archive file named Java™ Archive (JAR).
JAR file contains the class files and auxiliary resources
associated
1.) We first create a text file named Manifest.txt with the following contents:
Main-Class: MyPackage.MyClass
2.) We then create a JAR file named MyJar.jar by entering the following command:
jar cfm MyJar.jar Manifest.txt MyPackage/*.class
3.) When you run the JAR file with the following command, the main method of
MyClass executes: -
java -jar MyJar.jar

The jar command line options
Operation Command
To create a JAR file jar cf jar-file input-file(s)
To view the contents of a JAR file jar tf jar-file
To extract the contents of a JAR file jar xf jar-file
To run an application packaged as a
JAR file (requires the Main-class manifest
header)
java -jar app.jar

LAB - Creating Java Archive File (JAR) and Run application
outside the IDE
1.) Click “New ” from the project menu 2.) Select “JAR File”, click “OK”

outside the IDE
3.) Enter your application name “my_first_app” 4.) Click “Browse” to select the started class

outside the IDE
5.) Select the “Main Class Name:” which is “Class1” 6.) Click “OK”

outside the IDE
7.) Select “Deploy” from the project menu 8.) Click “Next”

outside the IDE
9) Click “Finish” 10.) Review the result jar file “my_first_app.jar”

outside the IDE
11.) Using Command Line Client to execute the JAR file
D:JDevelopermyworkApplication2Project1deploy>java -jar my_first_app.jar

Monitoring Basic Java Application
Using JConsole
The JConsole graphical user interface is a monitoring tool
that complies to the Java Management Extensions (JMX)
specification. JConsole uses the extensive instrumentation
of the Java Virtual Machine (Java VM) to provide information
about the performance and resource consumption of
applications running on the Java platform.
Starting JConsole
The jconsole executable can be found in JDK_HOME/bin, where JDK_HOME is the
directory in which the Java Development Kit (JDK) is installed. If this directory is in
your system path, you can start JConsole by simply typing jconsole in a command
(shell) prompt.

LAB – Monitoring Java Application with JConsole
1.) Create Java Application 2.) Deploy Java Application
Adding the loop into the code for long running app simulation.
for (int i=1; i<1000000; i++) {
System.out.println("Hi");
}

3.) Execute Java Application
>java -jar my_first_app.jar
4.) Start Jconsole and select your targeted
Java process
>jconsole

5.) Review Monitoring Results

6.) Exit the JConsole

Java Class
A class is a blueprint or prototype from which objects are
created. This section defines a class that models the state
and behavior of a real-world object. It intentionally focuses on
the basics, showing how even a simple class can cleanly
model state and behavior.

Java Object
Java Object is conceptually similar to real-world objects.
They consist of state and behavior.
An object stores its state in fields (variables) and exposes its
behavior through methods.
Methods operate on an object's internal state. Hiding internal
state is known as data encapsulation
Class
Object 1
Object 2
Blueprint
Instance

Java Variables
Class Variables (Static Fields)
The field member are declared as static modifier; this tells the
compiler that there is exactly one copy of this variable in
existence, regardless of how many times the class has been
instantiated.
Instance Variables (Non-Static Fields)
The field members are unique to each instance of a class the
instance.
Local Variables
The variable is declared in a method. Local variables are only
visible to the methods. they are not accessible from the rest of the
class.

Java Language Keywords
abstract continue for new switch
assert*** default goto* package synchronized
boolean do if private this
break double implements protected throw
byte else import public throws
case enum**** instanceof return transient
catch extends int short try
char final interface static void
class finally long strictfp** volatile
const* float native super while
*not used
**added in 1.2
***added in 1.4
****added in 5.0
Naming Convention:-
Do not use the Java Keywords as you variable.
Normally, The variable should start with lowercase and
follow by uppercase for the next word, eg. custArray,
printManager

Java Primitive Data Types
Default Value and Wrapper Class
The IEEE 754 Standard
The wrapper classes help you to perform conversion; eg converting String to integer:-
Interger.valueOf(“15”).intValue(); or int j = Integer.parseInt("10"); Please see java.lang.* library
Type Contains Default Size Range
Wrapper
Class
boolean true or false false 1 bit NA Boolean
char Unicode character u0000 16 bits u0000 to uFFFF Character
byte Signed integer 0 8 bits -128 to 127 Byte
Short
short Signed integer 0 16 bits -32768 to 32767 Integer
int Signed integer 0 32 bits -2147483648 to 2147483647 Long
long Signed integer 0 64 bits
-9223372036854775808 to
9223372036854775807
Character
float IEEE 754 floating point 0.0 32 bits ±1.4E-45 to ±3.4028235E+38 Float
double IEEE 754 floating point 0.0 64 bits
±4.9E-324 to
±1.7976931348623157E+308
Double
String is not a part of Java primitive data types.

Escape Character
Escape Sequence Character Value
b Backspace
t Horizontal tab
n Newline
f Form feed
r Carriage return
" Double quote
' Single quote
Backslash
uxxxx
The Unicode character with encoding xxxx, where
xxxx is four hexadecimal digits. Unicode escapes
can appear anywhere in a Java program, not only
in character and string literals.

Primitive Type Conversion
Convert
From:
Convert To:
boolean byte short char int long float double
boolean - N N N N N N N
byte N - Y C Y Y Y Y
short N C - C Y Y Y Y
char N C C - Y Y Y Y
int N C C C - Y Y* Y*
long N C C C C - Y* Y*
float N C C C C C - Y
double N C C C C C C -
The letter N in the table means that the conversion cannot be performed. The letter Y means that the conversion is a
widening conversion and is therefore performed automatically and implicitly by Java. The letter C means that the
conversion is a narrowing conversion and requires an explicit cast. Finally, the notation Y* means that the conversion is
an automatic widening conversion, but that some of the least significant digits of the value may be lost by the conversion.

Java Operators
Operators Precedence
postfix expr++ expr--
unary ++expr --expr +expr -expr ~ !
multiplicative * / %
additive + -
shift << >> >>>
relational < > <= >= instanceof
equality == !=
bitwise AND &
bitwise inclusive OR |
logical AND &&
logical OR ||
ternary ? :
assignment = += -= *= /=

LAB - ArithmeticDemo
class ArithmeticDemo {
public static void main (String[] args){
int result = 1 + 2; // result is now 3
System.out.println(result);
result = result - 1; // result is now 2
result = result * 2; // result is now 4
result = result / 2; // result is now 2
result = result + 8; // result is now 10
result = result % 7; // result is now 3
}
}

LAB - ConcatDemo
class ConcatDemo {
public static void main(String[] args){
String firstString = "This is";
String secondString = " a concatenated string.";
String thirdString = firstString+secondString;
System.out.println(thirdString);
}
}

LAB - UnaryDemo
class UnaryDemo {
int result = +1; // result is now 1
result--; // result is now 0
result++; // result is now 1
result = -result; // result is now -1
boolean success = false;
System.out.println(success); // false
System.out.println(!success); // true
}
}

LAB - PrePostDemo
class PrePostDemo {
int i = 3;
i++;
System.out.println(i); // "4"
++i;
System.out.println(++i); // "6"
System.out.println(i++); // "6"
}
}

LAB - ComparisonDemo
class ComparisonDemo {
int value1 = 1;
int value2 = 2;
if(value1 == value2) System.out.println("value1 == value2");
if(value1 != value2) System.out.println("value1 != value2");
if(value1 > value2) System.out.println("value1 > value2");
if(value1 < value2) System.out.println("value1 < value2");
if(value1 <= value2) System.out.println("value1 <= value2");
}
}

LAB - ConditionalDemo1
class ConditionalDemo1 {
int value1 = 1;
int value2 = 2;
if((value1 == 1) && (value2 == 2)) System.out.println("value1 is 1 AND
value2 is 2");
if((value1 == 1) || (value2 == 1)) System.out.println("value1 is 1 OR
value2 is 1");
}
}

LAB – ConditionalDemo2
class ConditionalDemo2 {
int value1 = 1;
int value2 = 2;
int result;
boolean someCondition = true;
result = someCondition ? value1 : value2;
}
}

Danairat T.
Line ID: Danairat
FB: Danairat Thanabodithammachari
+668-1559-1446
Thank you

02 basic java programming and operators

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