Browse Prior Art Database

Java Virtual Machine Byte Code Emulation

IP.com Disclosure Number: IPCOM000123763D
Original Publication Date: 1999-Apr-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 54K

Publishing Venue

IBM

Related People

Breslau, FC: AUTHOR [+3]

Abstract

Described is the capability of categorizing byte codes by Java application and defining emulator byte codes, where necessary. As Java Virtual Machines (JVMs) mature, new capability is introduced.

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This is the abbreviated version, containing approximately 61% of the total text.

Java Virtual Machine Byte Code Emulation

   Described is the capability of categorizing byte codes
by Java application and defining emulator byte codes, where
necessary.  As Java Virtual Machines (JVMs) mature, new capability is
introduced.

   Browsers containing JVMs are often standardized while new
applets are introduced which cannot run in the older JVMs.  By
categorizing byte codes used by an applet or Java application, a
quick comparison can be made between the byte codes executable by a
JVM and those present in an applet.  Emulation of newer byte codes
can be defined for older JVMs so that older JVMs can, if desired,
execute newer applets.  Emulator byte codes can be included in newer
applets so that these applets can be run in older JVMs.  Also, these
emulator codes can become part of the JVM so that they are
subsequently available for future applets.

   Thus when an applet is loaded, a list of byte codes used
by this applet is compared to the byte codes supported by the JVM.
If all of them are supported, the applet executes.  If some of them
are not, the applet sections containing the non-supported bytes codes
are checked to see if they are functionally critical for execution of
the applet.  Applet byte code identification, and a value
representing byte code criticality can be located in a newly defined
header section of each applet.  The header section will also contain
the list of included emulator byte codes and their location.  If the
applet sectio...