About java basics.why we need java ? what kind of a language is it? why is it called platform independent? java life cycle..............................................................................

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Why we need Java ???
 Originally for intelligent consumer-electronic devices (cell
phones)
 Then used for creating Web pages with dynamic content
 Now also used for:
Develop large-scale enterprise applications

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The Java Programming Language
• A high-level language
More close to human language
than machine language.

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The Java Programming Language
• Object-orientated programming
language
• Historically, a program has been viewed as a
logical procedure that takes input data, processes
it, and produces output data.
• Object-oriented programming (OOP) is a
programming language model organized
around objects rather than "actions" and data
rather than logic.
Yaaa I know it’s
not clear enough
I’ll explain it late
in another ppt.

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The Java Programming Language
• Platform independent
• Platform independent means that the code remains
the same irrespective of the platform involved.
• Java has something called a virtual machine called
JVM or Java Virtual Machine. What happens in case
of Java is that the JVM once installed on any
platform like windows or OS X can run the java code
without any alteration. The JVM acts like a virtual
platform on which the code is executed. As the
platform being JVM remains constant throughout all
platforms Java programs can run on any platform
irrespective of the real platform.

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The Java Programming Language
• Strongly-typed programming
language
• Java is a strongly typed programming language because
every variable must be declared with a data type.
• A variable cannot start off life without knowing the
range of values it can hold, and once it is declared, the
data type of the variable cannot change.

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The Java Programming Language
• Interpreted and compiled
language
• I’ll explain this in “Java Life Cycle”

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The Java Programming Language
• Automatic memory management
• Java Memory Management, with its built-in
garbage collection, is one of the language's
finest achievements.
• It allows developers to create new objects
without worrying explicitly about memory
allocation and DE allocation, because the
garbage collector automatically reclaims
memory for reuse.
• This enables faster development with less
boilerplate code, while eliminating memory
leaks and other memory-related problems

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The Java Platform
The Java Platform differs from most of the
other platforms.
Because it’s a software only platform.
Which will run on the top of other Hardware
based platforms.

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Edit
• Programmer writes
program (and stores
program on disk)
Compile
• Compiler creates bytecodes from
program (.class)
Load
• Class loader stores
bytecodes in memory
Execute
• Interpreter: translates
bytecodes into machine
language
Java Life Cycle

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END OF JAVA LESSON 1..