diff --git a/java/src/ch/ntb/usb/Device.java b/java/src/ch/ntb/usb/Device.java
index dd44d16..c27c6c7 100644
--- a/java/src/ch/ntb/usb/Device.java
+++ b/java/src/ch/ntb/usb/Device.java
@@ -147,9 +147,11 @@ public class Device {
 		}
 		release_interface(usbDevHandle, dev_interface);
 		if (LibusbWin.usb_close(usbDevHandle) < 0) {
+			usbDevHandle = 0;
 			throw new USBException("LibusbWin.usb_close: "
 					+ LibusbWin.usb_strerror());
 		}
+		usbDevHandle = 0;
 		maxPacketSize = -1;
 		logger.info("device closed");
 	}