Basic HTML version of Foils prepared 20 Sept 97

Foil 35 Java Features -- High Performance

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


1 Java interpreter performs on-the-fly runtime execution of the Java bytecodes which results typically in a satisfactory performance.
  • NOT true in initial software which is often 100 times slower than C
  • performance is improved in new "just-in-time" interpreters, which saves code for repeated sections to provide compiled code efficiency after first execution
2 Support for generating native machine code out of Java bytecodes, viewed as intermediate compiler form, is also provided and useful for performance demanding applications.
3 The performance of the machine code, generated from Java bytecodes, is comparable to that offered by typical C/C++ compilers on the same platform.
4 Several of these concepts are in fact similar as in the OSF/ANDF project. Using ANDF terminology, we would call Java compiler a 'producer', and the machine code generator discussed here, an 'installer'. Default Java working mode doesn't use installers but directly interprets the intermediate form (this mode is supported in ANDF by GAI -- Generalized ANDF Interpreter).
5 Java/HotJava system implements ANDF concepts for the Java language.

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© on Sun Oct 12 1997