I tried to write a simple program to retreive my topology and it produce the
following error:
Exception in thread "javax.usb Linux implementation Topology Poller"
java.lang.NullPointerException
at
com.ibm.jusb.os.linux.LinuxUsbServices.setActiveConfigAndInterfaceSettings(LinuxUsbServices.java:332)
at
com.ibm.jusb.os.linux.LinuxUsbServices.updateTopology(LinuxUsbServices.java:225)
at
com.ibm.jusb.os.linux.LinuxUsbServices.access$000(LinuxUsbServices.java:26)
at
com.ibm.jusb.os.linux.LinuxUsbServices$1.run(LinuxUsbServices.java:141)
at java.lang.Thread.run(Thread.java:595)
Looking at it, I noticed the error was caused by my APC UPS not returning a
valid configuration. The active config number returned was 98. It seems that it
being set correctly, but getAcitiveUsbConfiguration() returns null. This is how
I fixed it for myself:
UsbConfiguration usbConfig = device.getActiveUsbConfiguration();
if (usbConfig == null)
return;
//Iterator interfaces =
device.getActiveUsbConfiguration().getUsbInterfaces().iterator();
Iterator interfaces = usbConfig.getUsbInterfaces().iterator();
I'm not sure what's the best way to deal with it since it's the first day I'm
using javax.usb or anything usb.
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