INTRODUCION TO JAVA
Java is an Object Oriented Programming language created by James Gosling from Sun Microsystems (Sun) in 1991. Java is simple object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, multithreaded, high-performance and dynamic language. Java is a platform independent programming language. The syntax is similar to C++. Write a Java program once then it will run on multiple operating systems. The first Java version is released in 1995.
Like any other programming languages the Java programming language has it's own structure, syntax, and programming paradigm. The Java language's programming paradigm is based on the concept of OOP, which the language's features support. The Java language is a C language derivative, so syntax rules look much like C's. For example, code blocks are modularized into methods and delimited by braces ({ and }), and the variables are declared before they are used. Structurally, the Java language start with packages. A package is the Java languages namespace mechanism. Within packages are classes, and within classes are methods, variables, constants and more.
DEFINITION
Java is a general-purpose computer programming language that is concurrent, class-based, object oriented and specifically designed to have as few implementation dependencies as possible. It is indented to let application developers 'write once, run anywhere'. Meaning that compiled Java code can run all platforms that support Java without the need for recompilation. Java applications are typically compiled to byte code that can run on any Java Virtual Machine (JVM) regardless of computer architecture.
HOW JAVA DIFFER FROM C++?
JDK (Java Development Kit)
1- javac : This is a Java compiler used to convert the source code (.java file) to byte code (.class file).
2- java : It is an interpreter used to execute the byte code.
3- appletviewer : This is used to run applets without browsers being invoked.
4- javap : This tool is used to disassemble the Java byte code to display the member variables and the methods.
5- javah : This tool creates the C-header file necessary to extend your Java code with the C language.
6- javadoc : This tool is used to create documentation (comment entries) for the given Java code.
7- jdb : Java debugger is used to debug local and remote files.
8- jar : This tool is used to pack the collection of Java classes into single archive file.
DEFINITION
Java is a general-purpose computer programming language that is concurrent, class-based, object oriented and specifically designed to have as few implementation dependencies as possible. It is indented to let application developers 'write once, run anywhere'. Meaning that compiled Java code can run all platforms that support Java without the need for recompilation. Java applications are typically compiled to byte code that can run on any Java Virtual Machine (JVM) regardless of computer architecture.
HOW JAVA DIFFER FROM C++?
C++
|
Java
|
Compile to machine code
|
Compiled
to byte code.
|
Supports pointer
|
Does
not supports pointers
|
Global variables are allowed.
|
No
global variable concept
|
Multiple inheritances-A class can have two or more super
classes.
|
Multiple
inheritances are attained in directly with the help of interface concept.
|
Supports operator overloading.
|
Does
not support operator overloading.
|
ASCII- character set.
|
Unicode
– character set
|
JDK EDITIONS
1- Java Standard Edition (J2SE) : J2SE can be used to develop client-side standalone applications or applets. It contains JDK and API for Windows applications. It is core part of Java.
2- Java Enterprise Edition (J2EE) : J2EE can be used to develop server-side applications such as Java Servlets and Java Server Pages. It contains API that are used for building large web centric distributed applications.
3- Java Micro Edition (J2ME) : J2ME can be used to develop applications for mobile devices such as cell phones and portable devices.
1- Java Standard Edition (J2SE) : J2SE can be used to develop client-side standalone applications or applets. It contains JDK and API for Windows applications. It is core part of Java.
2- Java Enterprise Edition (J2EE) : J2EE can be used to develop server-side applications such as Java Servlets and Java Server Pages. It contains API that are used for building large web centric distributed applications.
3- Java Micro Edition (J2ME) : J2ME can be used to develop applications for mobile devices such as cell phones and portable devices.
JDK (Java Development Kit)
1- javac : This is a Java compiler used to convert the source code (.java file) to byte code (.class file).
2- java : It is an interpreter used to execute the byte code.
3- appletviewer : This is used to run applets without browsers being invoked.
4- javap : This tool is used to disassemble the Java byte code to display the member variables and the methods.
5- javah : This tool creates the C-header file necessary to extend your Java code with the C language.
6- javadoc : This tool is used to create documentation (comment entries) for the given Java code.
7- jdb : Java debugger is used to debug local and remote files.
8- jar : This tool is used to pack the collection of Java classes into single archive file.
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