Computer Basics: Computer introductions for beginners

Characteristics of Java
UNIT--3

• Java is simple
• Java is object-oriented
• Java is distributed
• Java is interpreted
• Java is robust
• Java is secure
• Java is architecture-neutral
• Java is portable
• Java’s performance
• Java is multithreaded
• Java is dynamic

Simple :
• Most of the concepts are drew from C++ thus
making Java learning simpler.
• No language is simple, but Java is a bit easier
than the popular object-oriented programming
language C++, which was the dominant
software-development language before Java.
• Java is partially modeled on C++, but greatly
simplified and improved.

Simple :
• For instance, pointers and multiple inheritance often
make programming complicated.
• Java replaces the multiple inheritance in C++ with a
simple language construct called an interface, and
eliminates pointers.
• The clean syntax makes Java programs easy to write
and read.
• Some people refer to Java as "C++--" because it is
like C++ but with more functionality and fewer
negative aspects.

• Java is small and simple language. Many
features of C and C++ are not part of Java
eg. : Java does not provide
•Pointers
•Preprocessors header file
•goto statements
•Operator overloading
•Multiple inheritance
Simple :

Object-oriented :
• Java programming is object-oriented
programming language.
• Like C++ java provides most of the object
oriented features.
• Java is pure OOP Language. (while C++ is semi
object oriented)

Object-oriented :
• Object oriented programming models the real
world in terms of objects.
• Everything in the world can be modeled as an
object.
• A circle is an object, a person is an object, and a
Window icon is an object.
• A Java program is object-oriented because
programming in Java is centered on creating
objects, manipulating objects, and making objects
work together.

Object-oriented :
• Object-oriented programming provides great
flexibility, modularity, clarity, and reusability
through encapsulation, inheritance, and
polymorphism
• Its simple, clean syntax makes programs easy to
write and read.
• Java programs are quite expressive in terms of
designing and developing applications.

Distributed :
• Distributed computing involves several
computers working together on a network.
• Java is designed to make distributed computing
easy.
• It has the ability to share both data and programs
• Since networking capability is inherently
integrated into Java, writing network programs is
like Sending and receiving data to and from a file.

Interpreted :
• You need an interpreter to run Java programs.
• The programs are compiled into the Java Virtual
Machine code called bytecode.
• The bytecode is machine-independent and can run
on any machine that has a Java interpreter, which
is part of the Java Virtual Machine (JVM).
• Most compilers, including C++ compilers,
translate programs in a high-level language to
machine code.
• The code can only run on the native machine.

• First Java compiler translates source code into
byte code instructions
• Byte codes are not machine instructions
• In the second stage Java interpreter generates
machine code
• That can be directly executed by the machine
Interpreted :

Robust :
• Java encourages error-free programming by being
strictly typed and performing run-time checks.
• Robust means reliable. No programming
language can ensure complete reliability.
• Java puts a lot of emphasis on early checking for
possible errors, because Java compilers can detect
many problems that would first show up at
execution time in other languages.
• Java also provides concept of exception handling
which identifies errors and eliminates.

Secure :
• Java provides a secure means of creating Internet
applications.
• Java provides secure way to access web
applications.
• As an Internet programming language, Java is
used in a networked and distributed environment.
• The absence of pointers in Java ensures that
programs cannot gain access to memory location
without proper initialization.

Architecture-neutral :
• Java is interpreted. This feature enables Java to
be architecture-neutral (platform-independent)
• With a Java Virtual Machine (JVM), you can
write one program that will run on any platform
• Java is not tied to a specific machine or
operating system architecture.
• Machine Independent i.e Java is independent of
hardware .

Architecture-neutral :
• Today, software vendors usually develop
multiple versions of the same product to run on
different platforms (Windows, OS/2, Macintosh,
and various UNIX, IBM AS/400, and IBM
mainframes).
• Using Java, developers need to write only one
version that can run on every platform.

Portable :
• The most significant feature of Java is its
portability
• Java programs can execute in any environment
for which there is a Java run-time system.(JVM)
• Platform Independent : Java programs can be
run on any platform (Linux,Window,Mac)
• Java programs can be easily moved from one
computer system to another ,anywhere and at
anytime

Once compiled, Java class file can be run on any platform

High performance :
• Bytecodes are highly optimized.
• JVM can executed them much faster .
• Users of the earlier Sun Java Virtual Machine
certainly noticed that Java was slow.
• However, the new JVM is significantly faster.
• The new JVM uses the technology known as just-in-
time compilation.

Multithreaded :
• Multithreading is a program’s capability to
perform several tasks simultaneously.
• For example, downloading a video file while
playing the video would be considered
multithreading.
• Java provides integrated support for
multithreaded programming.

Multithreaded :
• Multithreading is particularly useful in graphical
user interface (GUI) and network programming.
• In GUI programming, there are many things going
on at the same time.
• A user can listen to an audio recording while
surfing a Web page.
• In network programming, a server can serve
multiple clients at the same time.
• Multithreading is a necessity in multimedia and
network programming.

• Java is capable of dynamically linking new
• Class libraries
• Methods
• Objects
• Java programs supports functions written in
other languages such as C and C++
• These functions are known as “native methods”
Dynamic :

Dynamic :
• Java was designed to adapt to an evolving
environment.
• New class can be loaded on the fly without
recompilation.
• There is no need for developers to create, and for
users to install, major new software versions.

23
Frequently Asked Questions
• Explain the characteristics of Java.

24
• Java Is Simple
• Java Is Object-Oriented
• Java Is Distributed
• Java Is Interpreted
• Java Is Robust
• Java Is Secure
• Java Is Architecture-Neutral
• Java Is Portable
• Java's Performance
• Java Is Multithreaded
• Java Is Dynamic

• Java Is Simple
• Java Is Robust
• Java Is Secure
• Java Is Architecture-
Neutral
• Java Is Dynamic
Java is partially modeled on C+
+, but greatly simplified and
improved.
It Eliminates pointer and replace
multiple inheritance with interface.
Java is Easy to write and more
readable

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
Java is inherently object-
oriented.
Like C++ java provides most
of the object oriented features.
Java is pure OOP Language.
(while C++ is semi object
oriented)

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
Java is designed to make
distributed computing easy.
Since networking capability is
inherently integrated into Java,
writing network programs is like
sending and receiving data to
and from a file.

28
• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
You need an interpreter to run
Java programs.
The programs are compiled
into the Java Virtual Machine
code called bytecode.
The bytecode is machine-
independent and can run on any
machine that has a Java
interpreter.

29
• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
Robust means reliable.
Java has eliminated certain
types of error-prone
programming constructs.
For example: overwriting data
and corrupting the data
Java has a runtime exception-
handling feature to provide
programming support for
robustness.

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
As an Internet programming
language, Java is used in a
networked and distributed
environment
Java provides secure way to
access web applications.
Java implements several
security mechanisms to protect
your system against harm
caused by stray programs.

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
Also called platform-
independent.
Write once, run anywhere.
With JVM, you can write
one program that will run on
any platform.

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
Because Java is architecture
neutral, Java programs are
portable.
They can be run on any
platform without being
recompiled.

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
JVM can executed them much
faster .
Users of the earlier Sun Java
Virtual Machine certainly noticed
that Java was slow.
However, the new JVM is
significantly faster.

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
Multithreading is a program’s
capability to perform several
tasks simultaneously.
For example, downloading a
video file while playing the video
would be considered
multithreading.

• Java Is Simple
• Java Is Robust
• Java Is Secure
Neutral
• Java Is Dynamic
New class can load without
recompilation.
There is no need for
developers to create, and for
users to install, major new
software versions.
New features can be
incorporated transparently as
needed.

Computer Basics: Computer introductions for beginners

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