GCJ compiled SWT apps mysteriously rummaging the harddrive

Tue Feb 18 09:05:00 GMT 2003

Mark Wielaard writes:
 > Hi,
 > 
 > On Mon, 2003年02月17日 at 18:30, ÂŽÃ˜yvind Harboe wrote:
 > > SWT apps compiled with GCJ will mysteriously rummage the harddrive.
 > > 
 > > I thought I'd post a bit of information about this for posterity. 
 > > 
 > > Theory: Could it be that SWT is looking for classes? 
 > 
 > Yes!
 > 
 > > Class.forName("org.eclipse.swt.internal."+names[i]+".OS");
 > > [...]
 > > 18:22:01	HelloSWT.exe:112	IRP_MJ_CREATE	C:\temp\test\lib-org-eclipse-swt-internal-motif-OS	FILE NOT FOUND	Attributes: Any Options: Open 	
 > > 18:22:01	HelloSWT.exe:112	IRP_MJ_CREATE	C:\WINDOWS\System32\lib-org-eclipse-swt-internal-motif-OS	FILE NOT FOUND	Attributes: Any Options: Open 	
 > > 18:22:01	HelloSWT.exe:112	IRP_MJ_CREATE	C:\WINDOWS\system\lib-org-eclipse-swt-internal-motif-OS	FILE NOT FOUND	Attributes: Any Options: Open 	
 > > 
 > > ... lots more ...
 > 
 > This is a feature explained here:
 > http://gcc.gnu.org/onlinedocs/gcj/Extensions.html
 > 
 > When trying to load a class gnu.pkg.SomeClass the system
 > classloader will first try to load the shared library
 > lib-gnu-pkg-SomeClass.so, if that fails to load the class then
 > it will try to load lib-gnu-pkg.so and finally when the class is
 > still not loaded it will try to load lib-gnu.so. Note that all
 > .s will be transformed into -s and that searching for inner
 > classes starts with their outermost outer class. If the class
 > cannot be found this way the system classloader tries to use the
 > libgcj bytecode interpreter to load the class from the standard
 > classpath.
 > 
 > It does this so precompiled classes can be loaded automatically from
 > shared libraries so the class byte code doesn't have to be (slowly)
 > interpreted.
 > 
 > Maybe it would be good to make this into an option someone could disable
 > if they know there won't be any precompiled shared libraries.
Even if this facility were not available gcj would still mysteriously
rummage the harddrive looking for class files. After all, the only
reason this is happening is that the program asked to load a class.
Andrew.