What is Java?
Java is a relatively new programming language designed by Sun Microsystems for the internet.
Java characteristics:
Item # |
Characteristic |
Description |
1 |
Portable |
Compile Once Run Many Times |
2 |
Object Oriented |
Almost Everything is an Object |
3 |
Distributed |
Classes can be compiled on different machines |
4 |
Secure |
Java programs are placed in a restriced region of memory |
5 |
Safe |
Locations in memory can't be manipulated |
6 |
Simple |
Not really! |
7 |
etc. etc. etc. |
Multithreaded, Standard,... |
Comparing Languages: Old vs New
Item # |
C |
C++ |
Java |
1 |
platform dependent |
platform dependent |
platform independent |
2 |
compilation results in object code |
compilation results in object code |
compilation results in byte code |
3 |
Procedural |
object oriented |
object oriented |
4 |
memory is your responsibility |
memory is your responsibility |
memory is the system's responsibility |
5 |
running means till main ends |
running means till main ends |
running means till main ends and no more threads running in the JVM |
Java Development Kits
A Java program can be a stand-alone application or an applet that can be embedded into an html page.
To develop a Java program, you need the Java Development Kit (JDK), which can be obtained from: (partial list)
Please send questions or suggestions about this web page to beatnic@aset.psu.edu
ASET | ITS | Penn State
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