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Java for UD - Windows

Java wrappers and examples for the Windows UD library. The Windows UD library is the high-level Windows library/driver for the LabJack U3, U6 and UE9. For other LabJack devices, go to the Software page.

Warning: If you intend to create a 64-bit application please ensure you use AddRequestPtr/eGetPtr/ePutPtr rather than AddRequest/eGet/ePut anywhere you write or read an array of data. See our AddRequest documentation for more information.

The latest and recommended Java wrapper and examples for the Windows UD driver. Requires JNA and supports 32 and 64-bit Java and UD driver. Refer to the download's README.txt for requirements, compile/run instructions, documentation and license information.


The old Java wrapper and examples which are no longer updated. Uses a JNI dll and only supports 32-bit Java and UD driver. Refer to the text file in the zip for more information.


UD Library Overview

First read the general overview of the UD library.

The UD driver has a handful of functions, many with the same 4 to 6 parameters.


The main functions are used to build a list of requests (Add), execute the list (Go), and read the result of each request (Get).  Some functions (e.g. eGet) combine a single add/go/get into one function call.


The parameters are described at the bottom of the Overview page.  The meaning of each parameter should be apparent (e.g. Channel is the channel number you are operating on), but when it is not the pseudocode section of the device's datasheet has the extra information needed.

  • Handle:  Always the handle.

  • IOType:  Always the IOType.

  • Channel:  If something besides a channel number the pseudocode section will tell you.

  • Value:  Always the value.

  • X1:  Usually not used, but if used the pseudocode section will tell you.

  • UserData:  Usually not used, but if used the pseudocode section will tell you.


Device specific pseudocode can be found in the device datasheet pseudocode section (U3/U6/UE9).

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