JAVA FEATURES

Compiled and Interpreted

Java combines both these approaches thus making java a two-stage system. First, Java

compiler translates source code into what is known as bytecode instructions. Bytecode are not

machine instructions and therefore, in the second stage, Java Interpreter generates machine

code that can be directly executed by the machine that is running the Java Program.

Platform-Independent and Portable

Java is compiled to an intermediate form called Java Byte-Code or simply byte code. A Java

program never really executes immediately after compilation on the host machine. Rather,

this special program called the Java Interpreter or Java Virtual Machine reads the bytecode,

translates into the corresponding host machine instructions and then executes the machine

instruction. A java program can run on any computer system for which a JVM and some

library routines are installed. Because of Platform Independence Java programs can be

portable from a mini computer up to a super computer irrespective of H/W requirements and

OS Base.

Object-Oriented

Java is one of the Pure Object Oriented Programming Language where every construction of

the program should be written under the implementation of class which is the basic part of

OOPS.

Robust and Secure

Robustness is measured with the help of 2 concepts 1) Memory Management 2) Exception

Handling

In traditional applications, the programmer is responsible for both allocations and

de allocation of memory. In Java, Memory allocation is controlled by JVM where object

creation is done by the user de allocation is taken by Garbage Collector

In C,C++ error handling is done manually even before running the program. If any run-time

error comes the program is in inconsistent state which leads to memory leak. Java supports

pure exception handling which guards the program from abnormal situations.

Java is intended to work in networked and distributed environments by providing security.

Security becomes an important issue for a language that is used for programming on Internet.

Java Systems not only verify all memory access but also ensures that no viruses are communicated with an applet. The absence of pointers in Java ensures that programs cannot

gain access to memory locations without proper authorization.

Distributed

Java is designed as a distributed language for creating applications on networks. It has the

ability to share both data and programs. Java applications can open and access remote objects

on Internet as easily as they can do in a local system. This enables multiple programmers at

multiple remote locations to collaborate and work together on a single project.

Familiar, Simple and Small

By using Java different range of applications can be developed by keeping the common

structure which is understood by JVM. Java uses many constructs of C and C++ and

therefore, Java code looks like a C++ code.

Multithreaded and Interactive

Multithreaded means handling multiple tasks simultaneously. It is one of the important

features of Java that provides multi-tasking where 2 parts of a program can be runnable

concurrently by sharing the common block of resources. This feature greatly improves the

interactive performance of graphical applications.

High performance

Java performance is impressive for an interpreted language, mainly due to the use of

intermediate bytecode. Java architecture is also designed to reduce overheads during runtime.

Dynamic and Extensible

Java is capable of dynamically linking in new class libraries, methods and objects. In Java

classes that were unknown to a program when it was compiled can still be loaded into it at

runtime. Java programs support functions written in other languages such as C and C++.

Java Weaknesses:

Java is that it doesn’t directly support true decimal data.

Ex:

Double x = 5.02;

Double y = 0.01;

Double z = X + Y;

System.out.println(z);

Output:

5.029999999999999

But result is “5.03”