Features of Java

Java Programming Tutorial is a widely used robust technology. Let's start learning Java from basic questions like what is Java tutorial, Core Java, where it is used, what type of applications are created in Java, why use java and Java platforms.

         There is given many features of java. They are also known as java buzzwords. The Java Features given below are simple and easy to understand.

1.               Simple

2.               Object-Oriented

3.               Portable

4.               Platform independent

5.               Secured

6.               Robust

7.               Architecture neutral

8.               Dynamic

9.               Interpreted

10.          High Performance

11.          Multithreaded

12.          Distributed

Simple

According to Sun, Java language is simple because:

syntax is based on C++ (so easier for programmers to learn it after C++).

removed many confusing and/or rarely-used features e.g., explicit pointers, operator overloading etc.

No need to remove unreferenced objects because there is Automatic Garbage Collection in java. Best core java training in Bangalore

Object-oriented

Object-oriented means we organize our software as a combination of different types of objects that incorporates both data and behaviour.

Object-oriented programming(OOPs) is a methodology that simplify software development and maintenance by providing some rules.

Basic concepts of OOPs are:

1.        Object 2.        Class 3.        Inheritance 4.        Polymorphism 5.        Abstraction 6.        Encapsulation

Platform Independent

A platform is the hardware or software environment in which a program runs.

There are two types of platforms software-based and hardware-based. Java provides software-based platform.

The Java platform differs from most other platforms in the sense that it is a software-based platform that runs on the top of other hardware-based platforms. It has two components:

1.               Runtime Environment

2.               API(Application Programming Interface)

Java code can be run on multiple platforms e.g. Windows, Linux, Sun Solaris, Mac/OS etc. Java code is compiled by the compiler and converted into bytecode. This bytecode is a platform-independent code because it can be run on multiple platforms i.e. Write Once and Run Anywhere(WORA).

Secured

Java is secured because:

• No explicit pointer
• Java Programs run inside virtual machine sandbox
• Classloader: adds security by separating the package for the classes of the local file system from those that are imported from network sources.
• Bytecode Verifier: checks the code fragments for illegal code that can violate access right to objects.
• Security Manager: determines what resources a class can access such as reading and writing to the local disk.

These security are provided by java language. Some security can also be provided by application developer through SSL, JAAS, Cryptography etc. Advanced Java Training in Bangalore

Robust

Robust simply means strong. Java uses strong memory management. There are lack of pointers that avoids security problem. There is automatic garbage collection in java. There is exception handling and type checking mechanism in java. All these points makes java robust.

Architecture-neutral

There is no implementation dependent features e.g. size of primitive types is fixed.

In C programming, int data type occupies 2 bytes of memory for 32-bit architecture and 4 bytes of memory for 64-bit architecture. But in java, it occupies 4 bytes of memory for both 32 and 64 bit architectures.

Portable

We may carry the java bytecode to any platform.

High-performance

Java is faster than traditional interpretation since byte code is "close" to native code still somewhat slower than a compiled language (e.g., C++)

Distributed

We can create distributed applications in java. RMI and EJB are used for creating distributed applications. We may access files by calling the methods from any machine on the internet.

Multi-threaded

A thread is like a separate program, executing concurrently. We can write Java programs that deal with many tasks at once by defining multiple threads. The main advantage of multi-threading is that it doesn't occupy memory for each thread. It shares a common memory area. Threads are important for multi-media, Web applications etc.

Difference between JDK, JRE and JVM

1.               Brief summary of JVM

2.               Java Runtime Environment (JRE)

3.               Java Development Kit (JDK)

Understanding the difference between JDK, JRE and JVM is important in Java. We are having brief overview of JVM here.

If you want to get the detailed knowledge of Java Virtual Machine, move to the next page. Firstly, let's see the basic differences between the JDK, JRE and JVM.

JVM

JVM (Java Virtual Machine) is an abstract machine. It is a specification that provides runtime environment in which java bytecode can be executed.

JVMs are available for many hardware and software platforms. JVM, JRE and JDK are platform dependent because configuration of each OS differs. But, Java is platform independent.

The JVM performs following main tasks:

• Loads code
• Verifies code
• Executes code
• Provides runtime environment

JRE

JRE is an acronym for Java Runtime Environment.It is used to provide runtime environment.It is the implementation of JVM. It physically exists. It contains set of libraries + other files that JVM uses at runtime.

Implementation of JVMs are also actively released by other companies besides Sun Micro Systems.

JVM (Java Virtual Machine)

JVM (Java Virtual Machine) is an abstract machine. It is a specification that provides runtime environment in which java bytecode can be executed.

JVMs are available for many hardware and software platforms (i.e. JVM is platform dependent).

What is JVM

It is:

1.               A specification where working of Java Virtual Machine is specified. But implementation provider is independent to choose the algorithm. Its implementation has been provided by Sun and other companies.

2.               An implementation Its implementation is known as JRE (Java Runtime Environment).

3.               Runtime Instance Whenever you write java command on the command prompt to run the java class, an instance of JVM is created.

What it does

The JVM performs following operation:

• Loads code
• Verifies code
• Executes code
• Provides runtime environment

JVM provides definitions for the:

• Memory area
• Class file format
• Register set
• Garbage-collected heap
• Fatal error reporting etc.