when send print command displaying this messge only for this model : Zebra LP2824
java.lang.NullPointerException: Attempt to get length of null array
W/System.err: at java.lang.StringFactory.newStringFromBytes(StringFactory.java:46)
W/System.err: at com.zebra.sdk.comm.UsbConnection.getSerialNumberFromDevice(Unknown Source:28)
W/System.err: at com.zebra.sdk.comm.UsbConnection.loadSerialNumber(Unknown Source:24)
W/System.err: at com.zebra.sdk.comm.UsbConnection.loadDeviceMap(Unknown Source:10)
W/System.err: at com.zebra.sdk.comm.UsbConnection.(Unknown Source:29)
W/System.err: at com.zebra.sdk.comm.UsbConnection.(Unknown Source:4)
W/System.err: at com.zebra.sdk.printer.discovery.DiscoveredPrinterUsb.getConnection(Unknown Source:6)
W/System.err: at com.howmuch.pos.BarcodePrintActivity.printFormat(BarcodePrintActivity.java:398)
W/System.err: at com.howmuch.pos.BarcodePrintActivity$1$1.run(BarcodePrintActivity.java:138)
W/System.err: at java.lang.Thread.run(Thread.java:919)