2. Objectives
On completion of this period, you would be able to
know
• The features of Java Applets and Applications
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3. Recap
• What is an applet?
• Differentiate Java with C++
• Why Java is important to internet?
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4. Features of Java applications
Sun Micro Systems officially describes Java
with the following features
• Compiled and Interpreted
• Platform Independent and Portable
• Object Oriented
• Robust and Secure
• Distributed
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5. Contd..
Features of Java applications
• Simple, Small and Familiar
• Multithreaded and Interactive
• High Performance
• Dynamic and Extensible
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6. Compiled and Interpreted
• Usually a computer language is either compiled or
interpreted
• Java combines both these approaches, thus making
Java a two stage system
• First Java compiler translates source code into
byte code instructions
• Byte codes are not machine instructions
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7. Contd..
Compiled and Interpreted
• In the second stage Java interpreter generates
machine code
• That can be directly executed by the machine
Fig. 2.1 Compiled and Interpreted
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8. Platform Independent and Portable
• The most significant feature of Java is its
portability
• Java programs can be easily moved from one
computer system to another ,anywhere and at
anytime
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9. Platform Independent and Portable Contd..
• Changes and upgrades in
• Operating systems
• Processors
• System resources
will not force any changes in Java programs
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10. Platform Independent and Portable Contd..
Fig. 2.2 Once compiled, Java class file can be run on any platform
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11. Object Oriented
• Java is a true object oriented language
• Almost everything in Java is an object
• All programs code and data reside within objects
and classes
• Java comes with an extensive set of classes
arranged in packages
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12. Robust and Secure
• Java is a robust language
• It provides many safeguards to ensure reliable
code
• It has strict compile time and runtime for data
types
12
13. Contd..
Robust and Secure
• It is designed as a garbage collected language
• Java also provides concept of exception handling
which identifies errors and eliminates
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14. Contd..
Robust and Secure
• Security becomes an important issue for a
language that is used for programming on internet
• Threat of viruses and abuse of resources
• Java systems not only verify all memory access,
but also ensure that no viruses are communicated
with an applet
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15. Contd..
Robust and Secure
• The absence of pointers in Java ensures that
programs cannot gain access to memory location
without proper initialization
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16. Distributed
• Java is designed as a distributed language for
creating applications on networks
• It has the ability to share both data and programs
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17. Contd..
Distributed
• Java applications can open and access remote
object as easily as they can do in a local system
• Enables multiple programmers at multiple
locations work together on a single project
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18. Simple, Small and Familiar
• 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
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19. Contd..
Simple, Small and Familiar
• Familiarity is another feature of Java
• It is modeled on C and C++ languages
• Java is a simplified version of C++
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20. Multithreaded and Interactive
• Multithreaded means handling multiple
tasks simultaneously
• Java supports multithreaded programs
• Need not wait for the application to finish
one task before beginning another
• Greatly improves the interactive
performance of graphical applications
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21. High Performance
• Java performance is impressive for an interpreted
language
• Due to the use of intermediate byte code
• Java architecture is also designed to reduce
overheads during runtime
• The incorporation of multithreading enhances the
overall execution speed of Java programs
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22. Dynamic and Extensible
• Java is a dynamic language
• 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”
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23. Contd..
Dynamic and Extensible
• This facility enables the programmers to use the
efficient available in these languages
• Native methods are dynamically linked at runtime
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24. Summary
• Features of Java Applications
• Features of Java Applets
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25. Quiz
1.Usually a computer language is either ______
a) Compiled
b) Compiled and Interpreted
c) Compiled or Interpreted
d) Interpreted
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