core java - demo
TRANSCRIPT
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INTRODUCTION TO
JAVA
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1stGENERATION LANGUAGE
FEATURES :
It is known as Machine Language. It uses the Binary Language ( i.e, strings of 0s
and 1s)
Since the language is directly understandable tothe m/c, it is not in need of anyTranslator.
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DRAWBACKS :
Absolutely no readability to the programmers
Lot of complexity in the programming
Error debugging is very difficult
Purely depends on m/c architecture
Not a suitable language for all kinds ofApplications Designing
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2nd
GENERATION LANGUAGE
FEATURES :
It is known asASSEMBLY LANGUAGE. Symbolic codes are used as instructions.
They are English-like shortcut words which are
not directly understandable to the m/c. Hence, they need aTranslator, called
Assembler.
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ADVANTAGES :
To some extent, readability is increased
Complexity is reduced
Error debugging is made easier
DISADVANTAGES :
Purely depending on the m/c architecture Not suitable for all kinds of Applications
Designing
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The first two generation languages are known asLOW LEVEL LANGUAGES, since they havedirect interaction with the m/c parts.
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3rd
GENERATION LANGUAGE
FEATURES :
Purely independent of m/c architecture. More meaningful English-like words are used as
instructions.
Hence, they are in need of translators likeCompilers & Interpreters.
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ADVANTAGES :
More readability and less visible complexity
Error debugging is very easy
Coding flexibility is very high
Programs have high portability
Suitable for all kinds of applications designing
Some of the 3GLs are :PASCAL,COBOL,FORTRAN,C etc.,.
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4th
GENERATION LANGUAGE
Treated as Database Languages.
There are TWO types of Database Languages:
Non-procedural Languages
Procedural Languages
In case of Non-procedural Languages, it isenough to saywhat we want to have,but it is
not required to say how to do it.SQL is a standard Non-procedural
Language.
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In case of Procedural Language, it is required tosaywhat we want to have and how to do it.
The procedural languages change from softwareto software.
For example, PL/SQL is the procedurallanguage in Oracle; VBA is the procedurallanguage in MS-Access.
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5th
GENERATION LANGUAGE
The initial development of 5GLs is Object basedprogramming languages.
The next development to that is Object orientedprogramming languages.
OBPL = Encapsulation + Object IdentityOOPL = OBPL + Inheritance + Polymorphism
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In these two cases, the programming will bedone in terms of objects.
Objectis a physical entity which will have itsown state, unique identity and the behavior.
The state & identity of an object are specifiedwith the properties of it.
The behavior of an object is specified with the
operations done by it.
Properties are the data items & Operations
are the subprograms.
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Javas Lineage:
Java is related to C++, which is a directdescendent of C.
Much of the character of Java is inherited fromthese two languages.
From C, Java derives its syntax.
Many of Javas object-oriented features wereinfluenced by C++.
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The Creation of Java :
Java was conceived by James Gosling, PatrickNaughton, Chris Warth, Ed Frank, and MikeSheridan at SUN MICROSYSTEMS, Inc. in1991.
This language was initially named as Oak, byGosling,after an oak tree outside his window atSun.
When a group of Sun people visited a localcoffee shop, the name Javawas suggested.
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The primary motivation to develop Java was theneed for a platform-independent language that
could be used to create software to beembedded in various consumer electronicdevices, such as microwave ovens and remote
controls.About the time that the details of Java were
being worked out, a second, and ultimately more
important, factor was emerging that now plays acrucial role, theWorld Wide Web.
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Importance of Java to the Internet :
Java has a profound effect on the Internet.The reason for this is quite simple : Java expands
the universe of objects that can move about
freely in cyberspace. In a network, two very broad categories of
objects are transmitted between the server and
our personal computer :passive informationand dynamic, active programs.
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Java can be used to create two types ofprograms : applications and applets.
An applicationis a program that runs on ourcomputer, under the operating system of thatcomputer.
An appletis an application designed to betransmitted over the Internet and executed by aJava-compatible Web browser.
Java is able to address the two fundamental
problems associated with the applets :security and portability
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The key that allows Java to solve both thesecurity and the portability problems is that the
output of a Java program is not executable code.Rather, it is bytecode.
Bytecodeis a highly optimized set of
instructions designed to be executed by the Javarun-time system, which is called theJava VirtualMachine (JVM).
JVM is an interpreter for bytecode.Just In Time (JIT) is the compiler for bytecode.