Patch / workaround for kernel 2.6 (no components in pallet)

Question

Since I've read about this complaint all over the net, and, after three weeks without problems, I seem to have solved the issue locally (at least for Fedora Core II), here's a mini tutorial on how to do a patch so that Creator sucessfully copies the required user files to your ~/.Creator directory.
First, a bit of background. The reason the copy fails is because Creator uses FileChannel.transferTo, which is broken for JDK 1.4 under kernel 2.6 by changed behaviour of the sendfile kernel routine. The "fix" for the Sun jvm is to set the transferSupported flag of the runtime jar's FileChannelImpl class to false in the static initializer. We don't have the source and the flag is not publicly accessible, so we're going to patch the bytecode and put the patched class on Creator's bootclasspath...
0.) if you've alread started the IDE once, rembember to delete the ~/.Creator directory. The copy happens only when a user starts the IDE and it is noted that the .Creator durectory does not exist.
1.) Get and install NetBeans if you don't have it.
2.) Get and install the jasm.nbm (http://jasm.netbeans.org/servlets/ProjectDownloadList)
3.) unjar the java installation's rt.jar somewhere
4.) mount the directory where you unjared the rt.jar
5.) open the mounted folder and navigate to /sun/nio/ch package
6.) right-click over the FileChannelImpl class, and pick the Tools/Decompile by JRAW menu item
7.) the action should result in three new items in the file tree
8.) Double-click the new item: FileChannelImpl.jraw to edit it
9.) Do a search in the editor for "transferEnabled" You should find the first occurence around here:
<snip>
cp146: Utf8 "transferFrom" // transferFrom
cp147: Utf8 "transferFromArbitraryChannel" // transferFromArbitraryChannel
cp148: Utf8 "transferFromFileChannel" // transferFromFileChannel
cp149: Utf8 "transferSupported" // transferSupported
cp150: Utf8 "transferTo" // transferTo
cp151: Utf8 "transferTo0" // transferTo0
cp152: Utf8 "transferToArbitraryChannel" // transferToArbitraryChannel
cp153: Utf8 "transferToDirectly" // transferToDirectly
</snip>
But the occurrence we're really interested in is here:
<snip>
cp396: Field #cp207 #cp294 // sun.nio.ch.FileChannelImpl.readable boolean
cp397: Field #cp207 #cp295 // sun.nio.ch.FileChannelImpl.transferSupported boolean
cp398: Field #cp207 #cp296 // sun.nio.ch.FileChannelImpl.writable boolean
</snip>
This is where we find out the ConstantPool handle for the field itself.
10.) do a search from where you found the cp### for the field. In my case, it is cp397.
You should end up here, which is the static initializer for the class:
AccessFlag { ACC_STATIC }
// <clinit> () -> void
#cp8 // Utf8 "<clinit>"
#cp232 // Utf8 "()V"
Attributes {
Name #cp10 // Utf8 "Code"
Len 117 {
MaxStack 2
MaxLocals 0
Code { // 69
getstatic #cp400 // 178 1 144
ifnonnull 15 // 199 0 15
ldc #cp6 // 18 6
invokestatic #cp463 // 184 1 207
dup // 89
putstatic #cp400 // 179 1 144
goto 6 // 167 0 6
getstatic #cp400 // 178 1 144
invokevirtual #cp411 // 182 1 155
ifne 7 // 154 0 7
iconst_1 // 4
goto 4 // 167 0 4
iconst_0 // 3
putstatic #cp394 // 179 1 138
iconst_1 // 4
putstatic #cp397 // 179 1 141
invokestatic #cp488 // 184 1 232
invokestatic #cp433 // 184 1 177
putstatic #cp393 // 179 1 137
new #cp210 // 187 0 210
dup // 89
invokespecial #cp467 // 183 1 211
putstatic #cp405 // 179 1 149
ldc #cp5 // 18 5
ldc #cp4 // 18 4
invokestatic #cp487 // 184 1 231
putstatic #cp403 // 179 1 147
return // 177
Exceptions {
Attributes {
Name #cp17 // Utf8 "LineNumberTable"
Len 30 {
0 26
35 367
39 877
42 878
48 879
58 880
68 882
11.) do the patch
As you can see, above, the (cp397) field value is initialized to "true" (iconst_1, putstatic #cp397)
You want to change it so that it is initialized to false, like this:
putstatic #cp394 // 179 1 138
iconst_0 // 4
putstatic #cp397 // 179 1 141
invokestatic #cp488 // 184 1 232
12.) recompile the jraw files to a class file. Just select them and choose Build/Compile.
13.) make a jar with just the new, patched class file. Inside the jar, the file must sit in /sun/nio/ch to preserve the package structure.
14.) Change your Creator ide.cfg file, found in ${creator_home}/bin, so that the jar containing your patched class is prepended to creator's bootclasspath
Here's an example (I chose to install as root and used the default install to /opt...I've since changed the min and max stack, but nothing else, except the bootclasspath specification)
-J-Xms128m -J-Xmx128m
-J-Xbootclasspath/p:/opt/Creator/bin/fixFileChannelImpl.jar
-J-Xverify:none
-J-Dorg.netbeans.do_not_warn_default_package=true
-J-Dnetbeans.security.nocheck=true
-J-Dsunappsrvint.home=/opt/Creator/SunAppServer8
-jdkhome /usr/java/j2sdk1.4.2_05
Hope that helps,
boucherb@users,
The HSQLDB Development Group

Answer 1

Hi There,
Thank you for this very useful information.
Kishore