Error: Debug Component exceeds maximum size (65535 bytes)

Question

Hi All,
It would seem that I have come across a limitation in the CAP file format for Java Card 2.2.1. When I run the Sun 2.2.1 converter I get the following output:
Converting oncard package
Java Card 2.2.1 Class File Converter, Version 1.3
Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.
error:  Debug Component exceeds maximum size (65535 bytes).
Cap file generation failed.
conversion completed with 1 errors and 0 warnings.This also happens with JCDK 2.2.2. Is there any way around this limitation? I can instruct the compiler to not generate some of the debug output such as variable attributes, but this makes the debugger less than useful. I could not find anything in the JCVM spec for JC2.2.1 that mentions this limitation (I could have missed it very easily if it is there). Is this a limitation that will be lifted in new versions of the standard? This is tarting to be a bit of a problem as our code base has outgrown our development tools (no more debugger). Compiling and running without debug information works fine.
Any information on this would be much appreciated.
Cheers,
Shane

Answer 1

For those that are interested, I found this in the Java Card VM spec. u1 and u2 are 1 and 2 byte unsigned values respectively. It would appear that it is a limitation of the CAP file format. We have managed to work around this problem (parsing the debug component of the cap file was very informative) by shortening package names, reducing exception handling, and removing classes that we could do without.
It looks like this is removed for JC3.0 Connected Edition does not have this issue as it does not have CAP files, but JC2.2.2 and JC3.0 Classic Edition have this same issue. It would be nice if there was a converter/debugger combination that removed this limitation. If anyone knows of such a combination, I am all ears! I know for a fact that JCOP does not :(
Cheers,
Shane
*6.14 Debug Component*
This section specifies the format for the Debug Component. The Debug Component contains all the metadata necessary for debugging a package on a suitably instrumented Java Card virtual machine. It is not required for executing Java Card programs in a non-debug environment.
The Debug Component references the Class Component (Section 6.8 "Class Component”), Method Component (Section 6.9 "Method Component”), and Static Field Component (Section 6.10 "Static Field Component”). No components reference the Debug Component.
The Debug Component is represented by the following structure:
{code}
debug_component {
u1 tag
u2 size
u2 string_count
utf8_info strings_table[string_count]
u2 package_name_index
u2 class_count
class_debug_info classes[class_count]
{code}
The items in the debug_component structure are defined as follows:
*tag* tag item has the value COMPONENT_Debug (12).
*size* The number of bytes in the component, excluding the tag and size items. The value of size must be greater than zero.