Session 2 : Java Environment
Java
Environment
Q?
what are the features of Java.
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WORE : Write Once Run Everywhere . Platform Independent
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Dynamic : highly dynamic data structures, and we have a Run Time
loading and linking of the data
/> No
Memory Management Required: we have an automatic garbage collection
here which leads to No Memory Leaks
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Run-Time Checks,Compile-Time Checks , Strong Type Model and No
Explicit Pointer makes it a Very Robust Language
/> We
usually use exception mechanism to check errors
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Very easy to use : cos share similar syntax with other programming
languages likes C/C++
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Hierarchic way of representing classes(types) i.e. inheritance
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The first concept : class
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source code of class stays in className.java file
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execution of java starts from special method :
public
static void main(String[] args)
Q?
How does the process of Build and Run works in java
/1>
First.java file is passed through java compiler (javac)
/2>
Java compiler generates the byes code First.class (the extension of
byte code is .class)
/3>
java bytecode is passed through the Java Virtual machine and
generates the output
Q?
what does Java Virtual Machine (JVM) consists of.
/> It
consist of Interpreter, Just In Timer (JIT) compiler and Run Time
Compiler
Q?
how JVM loades the class .
/> on
the basis of classpath : (is the list of location where classes can
be loaded )
Q?
how java manages for large scale programming
/> By
providing certain features like :
1>
JavaDoc : Documentation on the info and use of the classes methods
2>
Class Libraries (Packages) : built in collection of standard classes
Others
Standard Utilities are :
1>
GUI : Graphica User Interface Library
2>
Concurrency (thread)
3>
Network Programming (library)
Q?
what is java development environment
/>
It consist of Java SE (Software Essentials) 7 :
http://www.oracle.com/technetwork/java/javase
this
software essentials consists of :
javac
Compiler
jdb
debugger
JRE
(Java Run Time Environment) – which consist of : JVM and some
Native packages like (awt , swing, system......)
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The Documentation is also privided to provide the info and use of all
the in built classes and its methods : http://docs.oracle.com/javase/
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Eclipse : This is the Integrated Development Environment (IDE) on
which we compile, debug and run java programs.
Note: *
eclipse use a different compiler than javac
Q?
what are some coding conventions in java.
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compound names : camelBackCapitalization
not underscore
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class names : Capitalized
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method names, variables – object instance name – attributes :
start in lower case
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constants : all uppercases
Q?
How import/export is done for java programs
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all the java programs are packaged and deployed jar file
Q?
what is this jar file
/>
they are the compressed archives and contains some meta-info
/> we
can easily execute this jar file from JVM
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