Overview and characteristics of Java
Java programming language was originally developed by Sun Microsystems which was initiated
by James Gosling and released in 1995 as core component of Sun Microsystems' Java platform
(Java 1.0 [J2SE]).
The latest release of the Java Standard Edition is Java SE 8. With the advancement of Java and
its widespread popularity, multiple configurations were built to suit various types of platforms.
For example: J2EE for Enterprise Applications, J2ME for Mobile Applications.
The new J2 versions were renamed as Java SE, Java EE, and Java ME respectively. Java is
guaranteed to be Write Once, Run Anywhere.
Java is −
Object Oriented − In Java, everything is an Object. Java can be easily extended since it
is based on the Object model.
Platform Independent − Unlike many other programming languages including C and C+
+, when Java is compiled, it is not compiled into platform specific machine, rather into
platform independent byte code. This byte code is distributed over the web and
interpreted by the Virtual Machine (JVM) on whichever platform it is being run on.
Simple − Java is designed to be easy to learn. If you understand the basic concept of OOP
Java, it would be easy to master.
Secure − With Java's secure feature it enables to develop virus-free, tamper-free systems.
Authentication techniques are based on public-key encryption.
Architecture-neutral − Java compiler generates an architecture-neutral object file
format, which makes the compiled code executable on many processors, with the
presence of Java runtime system.
Portable − Being architecture-neutral and having no implementation dependent aspects
of the specification makes Java portable. Compiler in Java is written in ANSI C with a
clean portability boundary, which is a POSIX subset.
Robust − Java makes an effort to eliminate error prone situations by emphasizing mainly
on compile time error checking and runtime checking.
Multithreaded − With Java's multithreaded feature it is possible to write programs that
can perform many tasks simultaneously. This design feature allows the developers to
construct interactive applications that can run smoothly.
Interpreted − Java byte code is translated on the fly to native machine instructions and is
not stored anywhere. The development process is more rapid and analytical since the
linking is an incremental and light-weight process.
High Performance − With the use of Just-In-Time compilers, Java enables high
performance.
Distributed − Java is designed for the distributed environment of the internet.
Dynamic − Java is considered to be more dynamic than C or C++ since it is designed to
adapt to an evolving environment. Java programs can carry extensive amount of run-time
information that can be used to verify and resolve accesses to objects on run-time.
java program compilation and execution process
Open notepad and add the code as of HelloWorld progam.
Save the file as: MyFirstJavaProgram.java.
, Open a command prompt window and go to the directory where you saved the class.
Assume it's C:\.
Type 'javac MyFirstJavaProgram.java' and press enter to compile your code. If there are
no errors in your code, the command prompt will take you to the next line (Assumption:
The path variable is set).
Now, type ' java MyFirstJavaProgram ' to run your program.
You will be able to see ' Hello World ' printed on the window
C:\> javac MyFirstJavaProgram.java
C:\> java MyFirstJavaProgram
Hello World
How to set the Temporary Path of JDK in Windows
To set the temporary path of JDK, you need to follow the following steps:
o Open the command prompt
o Copy the path of the JDK/bin directory
o Write in command prompt: set path=copied_path
Like this:
set path=C:\Program Files\Java\jdk1.6.0_23\bin
How to set Permanent Path of JDK in Windows
For setting the permanent path of JDK, you need to follow these steps:
o Go to MyComputer properties -> advanced tab -> environment variables -> new tab of
user variable -> write path in variable name -> write path of bin folder in variable value -
> ok -> ok -> ok
Write path in variable name: copy this path first be traversing in the folder where you installed
java.
Organization of java virtual machine
JVM (Java Virtual Machine) is an abstract machine. It is a specification that provides runtime
environment in which java byte code can be executed.
Java programming language was originally developed by Sun Microsystems which was initiated
by James Gosling and released in 1995 as core component of Sun Microsystems' Java platform
(Java 1.0 [J2SE]).
The latest release of the Java Standard Edition is Java SE 8. With the advancement of Java and
its widespread popularity, multiple configurations were built to suit various types of platforms.
For example: J2EE for Enterprise Applications, J2ME for Mobile Applications.
The new J2 versions were renamed as Java SE, Java EE, and Java ME respectively. Java is
guaranteed to be Write Once, Run Anywhere.
Java is −
Object Oriented − In Java, everything is an Object. Java can be easily extended since it
is based on the Object model.
Platform Independent − Unlike many other programming languages including C and C+
+, when Java is compiled, it is not compiled into platform specific machine, rather into
platform independent byte code. This byte code is distributed over the web and
interpreted by the Virtual Machine (JVM) on whichever platform it is being run on.
Simple − Java is designed to be easy to learn. If you understand the basic concept of OOP
Java, it would be easy to master.
Secure − With Java's secure feature it enables to develop virus-free, tamper-free systems.
Authentication techniques are based on public-key encryption.
Architecture-neutral − Java compiler generates an architecture-neutral object file
format, which makes the compiled code executable on many processors, with the
presence of Java runtime system.
Portable − Being architecture-neutral and having no implementation dependent aspects
of the specification makes Java portable. Compiler in Java is written in ANSI C with a
clean portability boundary, which is a POSIX subset.
Robust − Java makes an effort to eliminate error prone situations by emphasizing mainly
on compile time error checking and runtime checking.
Multithreaded − With Java's multithreaded feature it is possible to write programs that
can perform many tasks simultaneously. This design feature allows the developers to
construct interactive applications that can run smoothly.
Interpreted − Java byte code is translated on the fly to native machine instructions and is
not stored anywhere. The development process is more rapid and analytical since the
linking is an incremental and light-weight process.
High Performance − With the use of Just-In-Time compilers, Java enables high
performance.
Distributed − Java is designed for the distributed environment of the internet.
Dynamic − Java is considered to be more dynamic than C or C++ since it is designed to
adapt to an evolving environment. Java programs can carry extensive amount of run-time
information that can be used to verify and resolve accesses to objects on run-time.
java program compilation and execution process
Open notepad and add the code as of HelloWorld progam.
Save the file as: MyFirstJavaProgram.java.
, Open a command prompt window and go to the directory where you saved the class.
Assume it's C:\.
Type 'javac MyFirstJavaProgram.java' and press enter to compile your code. If there are
no errors in your code, the command prompt will take you to the next line (Assumption:
The path variable is set).
Now, type ' java MyFirstJavaProgram ' to run your program.
You will be able to see ' Hello World ' printed on the window
C:\> javac MyFirstJavaProgram.java
C:\> java MyFirstJavaProgram
Hello World
How to set the Temporary Path of JDK in Windows
To set the temporary path of JDK, you need to follow the following steps:
o Open the command prompt
o Copy the path of the JDK/bin directory
o Write in command prompt: set path=copied_path
Like this:
set path=C:\Program Files\Java\jdk1.6.0_23\bin
How to set Permanent Path of JDK in Windows
For setting the permanent path of JDK, you need to follow these steps:
o Go to MyComputer properties -> advanced tab -> environment variables -> new tab of
user variable -> write path in variable name -> write path of bin folder in variable value -
> ok -> ok -> ok
Write path in variable name: copy this path first be traversing in the folder where you installed
java.
Organization of java virtual machine
JVM (Java Virtual Machine) is an abstract machine. It is a specification that provides runtime
environment in which java byte code can be executed.
