By Amar Sivas | | Updated : 2019-05-26 | Viewed : 465 times
Java has created by James Gosling and his team in Sun Microsystems in 1991. Java is a popular and general-purpose programming language for software implementation. Java has been implemented with a principle called "Write Once, Run Anywhere" (WORA). The WORA means that Java code compiled within one Operating System can be executed in other Operating Systems without recompilation. Here Java code will be converted as “byte code” can be executed in any other operating system.
Java has initially started a research project for network devices. It is mainly designed for many varies of network devices. But it is changed and named OAK and then Green Project. It is finally renamed with Java. Sun Microsystems was release first java version Java 1.0 in 1991. When Java was introduced, the other option was C/C++ for application implementation. But C/C++ has some drawbacks. So that’s Sun Microsystems focused on some other language with some set of rules. So, with these set of rules, the developer will feel the programming very easy.
Simple and Objected Oriented: Programming will be very easy to learn and implementation When a programming language is simple and Object Oriented.
Compiled and Interpretable: Java is an independent language for all Operating Systems. The compiler will convert the .java file into .class file which is nothing but byte-code. This is nothing but Compilation. This is portable for all Operating Systems. The byte-code is not readable for Microprocessor. So JVM is will interpret it as binary code which is readable for microprocessors.
Robustness: Robustness means an efficient way for the usage of memory. Java has a better mechanism for efficiently handling Memory management. So Programming is not required for memory allocation and deallocation in C++.
Architectural Neutral: Java program will be executed irrespective of the environment.
Portability: Portability will allow the Program execution in different types of Operating Systems without modification. Means Write Program once and can be executed in other Operation Systems without modification.
High performance and Multithreaded: As Programming application can handle the data with multithreading in a better way, it will compute and provide results in less amount of time.
Secure: Java programming language is providing very good security features. So, the application will be very safe.
Dynamic: The application is highly portable for all Operating Systems. So, the applications can be downloaded anywhere in the network into system for application execution.
Before we start programming in Java, we need to know some common terms for better understanding the java.
JDK: Sun Microsystems introduced the JDK (Java Development Kit) as the main development environment which will be sufficient for development. It contains all other tools for development i.e. development Tools and JRE. These tools will be helpful for development. Although java language is OS platform independent, JDK is OS platform dependent. Java compiler will compile java file and create bytecode converted file i.e. .class file. This bytecode conversation file is not readable for the microprocessor. So, JVM will create a low-level conversation called binary code. So, this binary code should be platform dependent as it should be readable by Microprocessor. That’s why JDK means JRE and JVM are platform dependent. Due to this reason, JDK programmed as the OS platform depended. JDK will be programmed for those who want to implement the java programs.
JRE: It is a sub-component of the JDK. it will be called as Runtime Environment which will be used for only execution not for development. Technically, it is some part of the software that is mainly used for running the java programs. It contains ClassLoader, JVM and some class libraries. JRE is for end users who want to use Java applications.
Java Compiler: The compiler will compile the Java file and will generate the bytecode file which is nothing but .class file. As you know the language code should be machine readable format that is binary code. The compiled code which result the bytecode is not machine-readable format. So, the bytes code should convert as machine readable format.
JVM: In other programming languages the compiler will generate the machine-readable format code. But Java Compiler will generate the bytecode which is not machine-readable. But this is portable for types of Operating Systems. So, Microprocessor needs byte code as readable. JVM stands for Java Virtual Machine. So, JVM will tackle this problem where the byte code will be made as machine readable. JVM will convert the byte code as a Machine readable format that is binary code.
ClassLoader: ClassLoader is a subpart of JVM which will handle the class loading mechanism. The ClassLoader can easily identity .class file which contains the Java bytecode format.