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What is Java? Presentation On Introduction To Core Java By PSK Technologies (1)

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Learn JAVA tutorial -This Java tutorial is specially prepared for the Beginners who wants to learn Java programming language from the basics. This tutorial is prepared by Easy Web Solutions by PSK Technologies located in Nagpur that provides best training in Java,PHP,Web Development Hardware and Networking and also provide Internship on all mentioned courses – PowerPoint PPT presentation

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Title: What is Java? Presentation On Introduction To Core Java By PSK Technologies (1)


1
INTRODUCTION TOCORE JAVA
  • PSK TECHNOLOGIES
  • An ISO 90012015 (QMS) Certified IT Company
    Computer Education Software Development
    Computer Sales Services
  •  
  • Plot No-780, Near Durga Temple, Katol Road
    Chaoni, Nagpur-13
  • Phone 9975288300 / 9970141466
  • Email info_at_psktechnologies.co.in
  • website www.pskitservices.com

2
  • CONTENT
  • History
  • Several Java Version
  • Feature of java
  • Internal Detail
  • JVM
  • What is JVM
  • Variables
  • Data Type in java
  • Advantages of naming Convention in java

Website www.pskitservices.com Phone 9975288300
/ 9970141466
3
  • HISTORY Java is a general, all-purpose computer
    programming language that is circumstantial,
    class-based, object-oriented, and specially
    designed to have few application dependencies as
    possible. Java was developed initially for
    interactive television, but it was too advanced
    technology for the digital cable television
    industry at the time. It is proposed to let
    application developers write once, run anywhere,
    suggesting that compiled Java code can run on all
    platforms that condone Java without the necessity
    to recompile. Java applications are compiled to
    byte code that can run on any Java virtual
    machine (JVM) regardless of computer
    architecture.
  • James Gosling is generally credited as inventor
    of the Java programming language
  • First version released in 1995,Several java
    versions have been released, and they are
  • JDK Alpha and Beta (1995)
  • JDK 1.0 (23rd Jan 1996)
  • JDK 1.1 (19th Feb 1997)
  • J2SE 1.2 (8th Dec 1998)
  • J2SE 1.3 (8th May 2000)
  • J2SE 1.4 (6th Feb 2002)
  • J2SE 5.0 (30th Sep 2004)
  • Java SE 6 (11th Dec 2006)
  • Java SE 7 (28th July 2011)
  • Java SE 8 (18th March 2014)
  • Java SE 9 (21st Sep 2017)
  • Java SE 10 (20th March 2018)

Website www.pskitservices.com Phone 9975288300
/ 9970141466
4
  • FEATURES OF JAVAThe following are some important
    features of Java Programming Language
  • Simple
  • Platform Independent
  • Architectural Neutral
  • Dynamic and Extensible
  • Portable
  • Multi-Threading
  • Distributed
  • Networked
  • Secured
  • High Performance

Website www.pskitservices.com Phone 9975288300
/ 9970141466
5
  • Internal Details of Hello Java Program
  • What happens at compile time?At compile time,
    java file is compiled by Java Compiler (It does
    not interact with OS) and converts the java code
    into byte code.


  • Java Virtual Machine(JVM)
  • What happens At runtime ?
  • At runtime, following steps are performed
  • Class Loader Is the subsystem of JVM that is
    used to load class files
  • Byte Code Verifier Checks the code fragments for
    illegal code that can violate access right to
    objects.
  • Interpreter Read byte code stream then execute
    the instructions.

Website www.pskitservices.com Phone 9975288300
/ 9970141466
6
  • IMPORTANT DEFINATION
  • Class Keyword is used to declare a class in
    java.
  • Public Keyword is an access modifier which
    represents visibility, it means it is visible to
    all.
  • Static Is a keyword, if we declare any method
    as static, it is known as static method. The
    core advantage of static method is that there
    is no need to create object to invoke the
    static method. The main method is executed by the
    JVM, so it doesn't require to create object
    to invoke the main method. So it saves memory.
  • Void Is the return type of the method, it
    means it doesn't return any value.
  • Main Represents startup of the program.

Website www.pskitservices.com Phone 9975288300
/ 9970141466
7
  • Valid java main method signature
  • public static void main(String args)
  • public static void main(String args)
  • public static void main(String args)
  • public static void main(String... args)
  • static public void main(String args)
  • public static final void main(String args)
  • final public static void main(String args)
  • Final strictfp public static void main(String
    args)
  • Invalid java main method signature
  • public void main(String args)
  • static void main(String args)
  • public void static main(String args)
  • abstract public static void main(String args)

8
  • What is JDK, JRE and JVM
  • Understanding the difference between JDK, JRE and
    JVM is important in Java. We are having brief
    overview of JVM here.
  • JVM
  • JVM (Java Virtual Machine) is an abstract
    machine. It is a specification that provides
    runtime environment in which java byte code can
    be executed. JVM (Java Virtual Machine) is an
    abstract machine. It is a specification that
    provides runtime environment in which java byte
    code can be executed.
  •  The JVM performs following main tasks
  • Loads code
  • Verifies code
  • Executes code
  • Provides runtime environment

Website www.pskitservices.com Phone 9975288300
/ 9970141466
9
  • JRE
  • JRE is an acronym for Java Runtime Environment.
    It is used to provide runtime environment. It is
    the implementation of JVM. It physically exists.
    It contains set of libraries other files that
    JVM uses at runtime. Implementation of JVMs are
    also actively released by other companies Sun
    Micro Systems.
  • JDK
  • JDK is an acronym for Java Development Kit. It
    physically exists. It contains JRE development
    tools.

10
  • JVM (Java Virtual Machine)
  • JVM (Java Virtual Machine) is an abstract
    machine. It is a specification that provides
    runtime environment in which java byte code can
    be executed. JVMs are available for many hardware
    and software platforms (i.e. JVM is platform
    dependent).
  • What is JVM
  • It is A specification where working of Java
    Virtual Machine is specified. But implementation
    provider is independent to choose the algorithm.
    Its implementation has been provided by Sun and
    other companies.
  • An implementation its implementation is known as
    JRE (Java Runtime Environment).
  • Runtime Instance Whenever you write java command
    on the command prompt to run the java class, and
    instance of JVM is created.

Website www.pskitservices.com Phone 9975288300
/ 9970141466
11
  • What JVM does?
  • The JVM performs following operation
  • Loads code
  • Verifies code
  • Executes code
  • Provides runtime environment
  • JVM provides definitions for the
  • Memory area
  • Class file format
  • Register set
  • Garbage-collected heap
  • Fatal error reporting etc.

Website www.pskitservices.com Phone 9975288300
/ 9970141466
12
  • Internal Architecture of JVM
  • Let's understand the internal architecture of
    JVM. It contains class loader, memory area,
    execution engine etc. it Contain
  • Class loader
  • Class loader is a subsystem of JVM that is used
    to load class files.
  • Class (Method) Area
  • Class (Method) Area stores per-class structures
    such as the runtime constant pool, field and
    method data, the code for methods.
  • Heap
  • It is the runtime data area in which objects are
    allocated.

Website www.pskitservices.com Phone 9975288300
/ 9970141466
13
  • Stack
  • Java Stack stores frames. It holds local
    variables and partial results, and plays a part
    in method invocation and return.
  • Each thread has a private JVM stack, created at
    the same time as thread.
  • A new frame is created each time a method is
    invoked. A frame is destroyed when its method
    invocation completes.
  • Program Counter Register
  • PC (program counter) register. It contains the
    address of the Java virtual machine instruction
    currently being executed.
  • Native Method Stack
  • It contains all the native methods used in the
    application.
  • Execution Engine
  • A virtual processor
  • Interpreter Read byte code stream then execute
    the instructions.
  • Just-In-Time (JIT) compiler It is used to
    improve the performance. JIT compiles parts of
    the byte code that have similar functionality at
    the same time, and hence reduces the amount of
    time needed for compilation. Here the term?
    Compiler? Refers to a translator from the
    instruction set of a Java virtual machine (JVM)
    to the instruction set of a specific CPU.

14
  • Variable
  • Variable is name of reserved area allocated in
    memory.
  • Types of Variable
  • There are three types of variables in java
  • local variable
  • instance variable
  • static variable

 
  • Local Variable
  • A variable that is declared inside the method is
    called local variable.
  • Instance Variable
  • A variable that is declared inside the class but
    outside the method is called instance variable.
    It is not declared as static.
  • Static variable
  • A variable that is declared as static is called
    static variable. It cannot be local.

Website www.pskitservices.com Phone 9975288300
/ 9970141466
15
  • Data Types in Java
  • In java, there are two types of data types
  • Primitive data types
  • Non-primitive data types

Data Type Default Value Default Size
Boolean false 1 bit
Char '\u0000' 2 byte
Byte 0 1 byte
Short 0 2 byte
Int 0 4 byte
Long 0L 8 byte
Float 0.0f 4 byte
Double 0.0d 8 byte
Website www.pskitservices.com Phone 9975288300
/ 9970141466
16
  • Advantage of naming conventions in java
  • By using standard Java naming conventions, you
    make your code easier to read for yourself and
    for other programmers. Readability of Java
    program is very important. It indicates that less
    time is spent to figure out what the code does.

Name Convention
Class name Should start with uppercase letter and be a noun e.g. String , color Button, System, Thread etc.
interface name should start with uppercase letter and be an adjective e.g. Runnable, Remote, Action Listener etc.
method name should start with lowercase letter and be a verb e.g. action Performed(), main(), print(), println() etc.
variable name should start with lowercase letter e.g. first Name, order Number etc.
package name should be in lowercase letter e.g. java, Lang, sql, until etc.
constants name Should be in uppercase letter. e.g. RED, YELLOW, MAX_PRIORITY etc.
17
OUR SOFTWARE COURSES
Website www.pskitservices.com Phone 9975288300
/ 9970141466
18
OUR HARDWARE COURSES
MCITP
NETWORKING
HARDWARE
CCNA
LINUX
CCNP
Website www.pskitservices.com Phone 9975288300
/ 9970141466
19
OUR SERVICES
WEBSITE DESIGNING DEVELOPMENT
Website www.pskitservices.com Phone 9975288300
/ 9970141466
20
IT TRAINING
Website www.pskitservices.com Phone 9975288300
/ 9970141466
21
DIGITAL MARKETING
Website www.pskitservices.com Phone 9975288300
/ 9970141466
22
LAPTOP SALES AND SERVICES
Website www.pskitservices.com Phone 9975288300
/ 9970141466
23
THANK YOU
PSK TECHNOLOGIES PVT. LTD. IT
COMPANY
FOLLOW US ON
Address Plot no-780, Near Durga Temple,
Katol Road Chhaoni, Nagpur-13
https/www.pskitservices.com
Contact 9975288300
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