PrintServiceLookup - Will not list all printers on a print job queue

Question

I have a simple class that fetches all the attached printers to a Linux system (with CUPS).
It returns, correctly, list of three printers.
PrintService[] printerServiceList;
printerServiceList = PrintServiceLookup.lookupPrintServices(null, null);
for (int i = 0; i < printerServiceList.length; i++) {
      System.out.println(printerServiceList.getName());
None of the three printers are physically attached to the Linux server.
If I fire a print to Printer1 or Printer2, the jobs just remain in the queue. However, if I fire print to Printer3, +strange+ thing happens.
*The above PrintServiceLookup code stops returning Printer2 and Printer3. It just lists Printer1 as the avilable print service.*
CUPS still shows all the three printers as available. (Restart of the VM does not help - same behavior, lists only 1 printer).
The main difference between Printer1, 2 and Printer3 is that the DeviceURI of Printer1 and Printer2 are
socket://172.x.x.1/queue1
While the deviceURI of the Printer3 is
lpd://172.x.x.8/queue3
If I remove Printer3 from the printers on CUPS, everything works fine after it.
Also, if I just change the deviceURI of Printer3 to socket://... it starts behaving normally. (Of cource, I cannot do this).
What is happening here? Why is lpd causing that printer and an unrelated Printer2 not to be return by the print API? I would tend to believe that it is a Java API bug.
Any pointers or work-arounds would be really appreciated.
Thanks,
-jas
Edited by: jaswinder_singh on Nov 10, 2009 12:27 AM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

Hello SeaDragon47.
The easiest solution to the "not waking from sleep" issue is to simply plug the printers directly into the wall outlet.  Something about the manner in which surge protectors/power strips handle electricity doesn't sit quite right when electronics want to wake up. 
Another possibility is to upgrade the firmware on the printers.  Here is the latest firmware for the Officejet 4620.  The Photosmart does not appear to have upgradable firmware.  
Yet another suggestion is to set static IP addresses for the printer(s).  I am not sure why but having a static IP set seems to keep the printer from going into sleep mode in the first place.
Let me know if this helps.  Have a lovely day.
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