Features
(or) aspects
|
C
language
|
C++
language
|
Java
|
Successor of
|
BCPL
|
C
|
C &C++
|
Pointers
|
supports
|
supports
|
Not support
|
Storage classes:
auto, extern
|
support
|
support
|
Not support
|
template
|
Not support
|
support
|
Not support
|
DMA functions
|
malloc(), calloc(),
realloc(),
free()
|
new, delete
|
Garbage collectors
|
destructor
|
Not support
|
support
|
Not support
|
Database connectivity
|
Not support
|
Not support
|
support
|
Exception handler
|
Not support
|
support
|
support
|
UNIT-1
Chapter 1
Java lineage
ü Java is related to c++.
ü Java is directly inherited from c and c++.
ü Most of the characters, characteristics were
inherited from both c and c++.
ü Java derives its syntax from c.
ü Most of the oops features in java is derived
from c++.
Creation of java
v In 1991 James Gosling and his team to
contribute hard work for developing the Java.
v Java programming language was
designed at Sun Micro systems.
v The initial version of java nearly
took 18 months for its implementation.
v The initial version of java is called
as Oak.
v In 1995 Oak was renamed to java.
v After 1995 java was recognized by the
computer users.
v Most of the java features were
derived from c and c++.
How java changed internet
Most of the internet applications like
web-browsers are developed with the help of java script language.
Ø Java script follows java features.
Ø In a network two categories of
objects are transmitted in between server and our personal computers (clients),
which provide static and dynamic information.
Ex: If
we want to check our mail id’s (or) any other social networks, initially we
have to login.
Ø Java
programs are very important for internet due to the following reasons
a. Security
b. Portable
a)
Security:
Java programs will provide more secure than others.
ü Suppose every time that we want to download a
normal app from the browsers from any point they will get viral infection
(virus).
ü Java will provide firewall features for
detecting the virus.
ü As firewall is software.
ü By providing the firewalls we can maintain
security for the following areas.
i. Credit card details
ii. Bank account balance.
iii. Passwords
iv. By searching the contents of our computer
local files etc.,
ü We ever we use a java compactable
web-browsers, you can safely download without fear of viral –infections.
b)
Portability:
It is another important feature from java programming language.
ü Portable means or transfer.
ü Now a day’s most of the people that they are
using computers with several operating systems; computers are connected to
internet for various reasons.
ü Once we can write java program, that program
can run in computers, operating systems with or without small modifications.
This feature is refers to portable.
Ø Java
applet programs are used for internet purpose.
Applet
An applet is
a special kind of java program i.e., is designed to transmit over the internet
network and automatically executed by the java compactable web-browsers.
Ex: Images,
sound files, video files.
Or
An applet is
a special kind of java program that will react to user input and dynamically
change.
Byte code
v Most of the Java programs provide both
security and portability.
v The output of Java compiler is not executable
code rather than it is Byte code.
v Byte code is highly optimized set of
instructions that are designed to be executed by Java Virtual Machines (or)
Java Runtime Machines (JVM).
v JVM is an interpreter for Byte code.
v Java programs are interpreted by the JVM that
helps to solve the major problems associated with downloaded programs over the
internet.
v Translating Java programs into Byte code makes
it easy to run a program in several environments.
v When a program is compiled to an intermediate
form and then interpreted by JVM, it
runs slower than the compiled to executable code because Byte code has been highly optimized, the use of Byte code enables the JVM to execute programs much faster than the others.
v Java programs are executed by JVM, such
programs will provide more secure.
v Sun Micro systems Hotspot technology for
compilation process, Hotspot technology will provides JIT (Just In Time)
compilers for Byte code.
v JIT stands for Just In Time.
v JIT compiler is a part of JVM, which is used
to compile the select portion of Byte code into executable code.
Java Buzz Words
Java contains several functions or Buzz
words such as
1. Simple
2. Secure
3. Portable
4. Object Oriented
5. Robust
6. Multithread
7. Distributed
8. Interpreted and High performance
9. Dynamic
1)
Simple:
ü It is a first feature from Java.
ü Java was designed to be easy for programmers
to learn and use effectively.
ü By using the C syntaxes and C++ structures
Java was designed.
ü If we know about oops features, simply we can
write a Java program.
2)
Secure:
ü Java programs will provide more secure than
the others.
ü Suppose every time we want to download a
normal app from the browsers at any point the device will get viral infection
(virus).
ü Java will provide “Firewall” feature for
detecting the virus.
ü Firewall provides the communication in between
network application and over computer.
ü Firewall is software.
ü By providing the Firewall we can maintain
security for the following areas;
a. Credit card details
b. Bank Account Balance
c. Passwords
d. By searching the contents of our computer
local file systems etc.,
ü Whenever we use a Java compatible web
Browsers, we can safely download without fear of viral infections.
3)
Portability:
ü It is another important feature from Java
programming language.
ü Portable means move or transfer.
ü Now a days, most of the people are using
computers with several operating systems, computers are connected to internet
for various reasons.
ü Once we write a Java program, that program can
run in any computers, operating systems with (or) without small modifications.
This feature is refers to portable.
