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History of Java Programming Essay Sample

History of Java Programming Pages
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Java was created in 1991 by James Gosling, Mike Sheridan, and Patrick Naughton of Sun Microsystems and was released in 1995 as a core component of Sun Microsystems’ Java Platform. Initially called Oak, in honor of the tree outside Gosling’s window, its name was changed to Java because there was already a language called Oak.

The original motivation for Java was the need for platform independent language that could be embedded in various consumer electronic products like toasters and refrigerators. One of the first projects developed using Java was a personal hand-held remote control named Star 7.

At about the same time, the World Wide Web and the Internet were gaining popularity. Gosling et. al. realized that Java could be used for Internet programming. Principles
There were five primary goals in the creation of the Java language:

It should be “simple, object-oriented and familiar”.
It should be “robust and secure”.
It should be “architecture-neutral and portable”.
It should execute with “high performance”.
It should be “interpreted, threaded, and dynamic”.

Nature of the Java Language

A programming language
As a programming language, Java can create all kinds of applications that you could create using any conventional programming language.

A development environment
As a development environment, Java technology provides you with a large suite of tools: a compiler, an interpreter, a documentation generator, a class file packaging tool, and so on.

An application environment
Java technology applications are typically general-purpose programs that run on any machine where the Java runtime environment (JRE) is installed.

A deployment environment
There are two main deployment environments: First, the JRE supplied by the Java 2 Software Development Kit (SDK) contains the complete set of class files for all the Java technology packages, which includes basic language classes, GUI component classes, and so on. The other main deployment environment is on your web browser. Most commercial browsers supply a Java technology interpreter and runtime environment.

Some Features of Java:

The Java Virtual Machine

The Java Virtual Machine is an imaginary machine that is implemented by emulating software on a real machine. The JVM provides the hardware platform specifications to which you compile all Java technology code. This specification enables the Java software to be platform-independent because the compilation is done for a generic machine known as the JVM.

A bytecode is a special machine language that can be understood by the Java Virtual Machine (JVM). The bytecode is independent of any particular computer hardware, so any computer with a Java interpreter can execute the compiled Java program, no matter what type of computer the program was compiled on.

Garbage Collection

Many programming languages allow a programmer to allocate memory during runtime. However, after using that allocated memory, there should be a way to deallocate that memory block in order for other programs to use it again. In C, C++ and other languages the programmer is responsible for this. This can be difficult at times since there can be instances wherein the programmers forget to deallocate memory and therefore result to what we call memory leaks.

In Java, the programmer is freed from the burden of having to deallocate that memory themselves by having what we call the garbage collection thread. The garbage collection thread is responsible for freeing any memory that can be freed. This happens automatically during the lifetime of the Java program.

Code Security

Code security is attained in Java through the implementation of its Java Runtime Environment (JRE). The JRE runs code compiled for a JVM and performs class loading (through the class loader), code verification (through the bytecode verifier) and finally code execution.

The Class Loader is responsible for loading all classes needed for the Java program. It adds security by separating the namespaces for the classes of the local file system from those that are imported from network sources. This limits any Trojan horse applications since local classes are always loaded first. After loading all the classes, the memory layout of the executable is then determined. This adds protection against unauthorized access to restricted areas of the code since the memory layout is determined during runtime.

After loading the class and layouting of memory, the bytecode verifier then tests the format of the code fragments and checks the code fragments for illegal code that can violate access rights to objects.

After all of these have been done, the code is then finally executed.

Phases of a Java Program

The first step in creating a Java program is by writing your programs in a text editor. Examples of text editors you can use are notepad, vi, emacs, etc. This file is stored in a disk file with the extension .java.

After creating and saving your Java program, compile the program by using the Java Compiler. The output of this process is a file of Java bytecodes with the file extension .class.
The .class file is then interpreted by the Java interpreter that converts the bytecodes into the machine language of the particular computer you are using. TaskTool to useOutput
Write the programAny text editorFile with .java extension
Compile the programJava CompilerFile with .class extension (Java bytecodes) Run the programJava InterpreterProgram Output

Creating your first Java Program

public class Hello
{
/**
* My first java program
*/
public static void main(String[] args) {

//prints the string “Hello world” on screen
System.out.println(“Hello world!”);

}
}

2 Methods of creating a Java Program

a)Using a Text Editor and Console

Examples of Text Editors: Notepad, VI, emacs, MSWord, Wordpad, Open Office Text Document, etc.

Steps in creating a Java Program:
Step 1: Start the Text Editor
Step 2: Write the source code of your Java Program in the Text Editor
Step 3: Save your Java Program (.java)
Step 4: Open Command Console (cmd)
Step 5: Compile your Program
-Change directory
-javac [filename w/ file extension]
Step 6: Run the Program
-java [filename w/o file extension]

b)Using an Integrated Development Environment

Integrated Development Environment – a programming environment integrated into a software application that provides a GUI builder, a text or code editor, a compiler and/or interpreter and a debugger.

Steps in creating a Java Program:
Step 1: Install JDK (Java Development Kit)
Step 2: Install IDE (JCreator)
Step 3: Configure JDK profile (Set the location for JDK)
Step 4: Open JCreator
Step 5: Create New File (Java Class)
Step 6: Write the source code of your Java Program in the IDE
Step 7: Save your Java Program (.java)
Step 8: Compile your Program using the IDE
Step 9: Run the Program using the IDE

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