Introduction To Java
Java is a complete programming
language developed by Sun. It Can be used to develop either web based or
stand-alone software. Many pre-created code libraries available for more
complex and powerful programs
Following are the features of JAVA
- Simple
- Object-Oriented
- Portable
- Platform independent
- Secured
- Robust
- Architecture neutral
- Dynamic
- Interpreted
- High Performance
- Multithreaded
- 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. |
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: |
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:
- Runtime Environment
- 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).
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.
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