Basic HTML version of Foils prepared 20 Sept 97

Foil 30 Java Features -- It's Portable

From Java Tutorial - Summer 1997 Part 1:Introduction to Java Language CEWES Tutorial, Classes SU/Jackson State -- July 22-25 and Fall 97. by Nancy J. McCracken,Geoffrey C. Fox


Java language offers a uniform abstract (virtual) machine model which is identical for all platforms.
SUN owns the Java Virtual Machine (see online report) -- it is universal while classes can be added by any user
Unlike in C/C++ where various integers match the architecture of a physical machine at hand, Java byte, char short, int and long are always of the same size, equal to 8, 16, 16(unicode), 32 and 64 bits, respectively.
  • No header files, preprocessors,#define etc.
  • floating point is always IEEE 754
Differences between vendor specific windowing environments (X Windows, MS Windows, Macintosh) are removed in terms of the Abstract Windowing Toolkit (AWT) metaphor.
AWT is given by ~60 Java classes (alpha) which offer a universal GUI programming model, portable between UNIX, PC and Mac, and translated automatically to native windowing systems on individual platforms by Java interpreters.



© on Sun Oct 12 1997