Read more
Introduction
Java is a programming language created by James Gosling from Sun Microsystems (Sun) in 1991. The target of Java is to write a program once and then run this program on multiple operating systems. The first publicly available version of Java (Java 1.0) was released in 1995. Sun Microsystems was acquired by the Oracle Corporation in 2010. Oracle has now the steermanship for Java. In 2006 Sun started to make Java available under the GNU General Public License (GPL). Oracle continues this project called OpenJDK.
Over time new enhanced versions of Java have been released. The current version of Java is Java 1.8 which is also known as Java 8.
Java is defined by a specification and consists of a programming language, a compiler, core libraries and a runtime (Java virtual machine) The Java runtime allows software developers to write program code in other languages than the Java programming language which still runs on the Java virtual machine. The Java platform is usually associated with the Java virtual machine and the Java core libraries.
JAVA language properties
Platform independent: Java programs use the Java virtual machine as abstraction and do not access the operating system directly. This makes Java programs highly portable. A Java program (which is standard-compliant and follows certain rules) can run unmodified on all supported platforms, e.g., Windows or Linux.
Object-orientated programming language: Except the primitive data types, all elements in Java are objects.
Strongly-typed programming language: Java is strongly-typed, e.g., the types of the used variables must be pre-defined and conversion to other objects is relatively strict, e.g., must be done in most cases by the programmer.
Interpreted and compiled language: Java source code is transferred into the bytecode format which does not depend on the target platform. These bytecode instructions will be interpreted by the Java Virtual machine (JVM). The JVM contains a so called Hotspot-Compiler which translates performance critical bytecode instructions into native code instructions.
Automatic memory management: Java manages the memory allocation and de-allocation for creating new objects. The program does not have direct access to the memory. The so-called garbage collector automatically deletes objects to which no active pointer exists.
myValue and myvalue are treated as different variables.Programming in java
Java source files are written as plain text documents. The programmer typically writes Java source code in an Integrated Development Environment (IDE) for programming. An IDE supports the programmer in the task of writing code, e.g., it provides auto-formating of the source code, highlighting of the important keywords, etc.
At some point the programmer (or the IDE) calls the Java compiler ( javac ). The Java compiler creates the bytecode instructions. These instructions are stored in .class files and can be executed by the Java Virtual Machine
Uses of JAVA
Java, not unlike many of the technologies which influence our everyday lives to this very day, originated in California, under the purview of Sun Microsystems, a company founded in 1982 by Andreas Bechtolsheim, Vinod Khosla, and Scott McNeally. With that said, tech-savvy types tend to look more to the future than the past, so if you find yourself more curious about the modern world of coding, or find yourself questioning just how influential Java has been to the world of technology, you don’t particularly want a history lesson. You’re most likely looking for the modern applicability and influence of a technology that has continued to evolve consistently in order to keep up with the times.
Java is a programming language, designed to be concurrent, class-based and object-oriented, as well as a computing platform first released by Sun Microsystems in 1995. An enormous amount of applications and websites will not work unless you have Java installed, and more are created every day. Denying yourself Java is akin to denying yourself access to a technological infrastructure. Java is advertised, and esteemed for its fast performance, security, and reliability.
compare java to python
Python programs are generally expected to run slower than Java programs, but they also take much less time to develop. Python programs are typically 3-5 times shorter than equivalent Java programs. This difference can be attributed to Python's built-in high-level data types and its dynamic typing. For example, a Python programmer wastes no time declaring the types of arguments or variables, and Python's powerful polymorphic list and dictionary types, for which rich syntactic support is built straight into the language, find a use in almost every Python program. Because of the run-time typing, Python's run time must work harder than Java's. For example, when evaluating the expression a+b, it must first inspect the objects a and b to find out their type, which is not known at compile time. It then invokes the appropriate addition operation, which may be an overloaded user-defined method. Java, on the other hand, can perform an efficient integer or floating point addition, but requires variable declarations for a and b, and does not allow overloading of the + operator for instances of user-defined classes.
For these reasons, Python is much better suited as a "glue" language, while Java is better characterized as a low-level implementation language. In fact, the two together make an excellent combination. Components can be developed in Java and combined to form applications in Python; Python can also be used to prototype components until their design can be "hardened" in a Java implementation. To support this type of development, a Python implementation written in Java is under development, which allows calling Python code from Java and vice versa. In this implementation, Python source code is translated to Java bytecode (with help from a run-time library to support Python's dynamic semantics).
0 Reviews