Logging is only recommend while troubleshooting. It is necessary to reboot the device to apply registry setting changes.

This page provides some common issues and suggested resolutions for using the Java Access Bridge (JAB) feature of Blue Prism.

The target application crashes when highlighting or accessing elements

If elements spy correctly, but then the target application crashes when attempting to highlight or otherwise interact with those elements, the problem is likely to be caused by a flaw in the Java Access Bridge components, which have problems with large numbers (approximately 200 or more) or elements on a single screen. You can prevent this crashing by enabling the 'descendtree' target application option in Application Modeller. This mode is significantly slower, so should only be used when necessary.

JAB versions

It is recommended to use the latest possible JAB version for the installed JRE. Since JRE7u6, JAB 2.0.3 comes bundled with the java installer. Since Jre7u60, JAB 2.0.4 is bundled.

JRE Version	JAB Version
Below JRE5	2.0.1 or 2.0.0
JRE5 and later	2.0.2
JRE6 and later	2.0.2
JRE7 and later	2.0.4

Blueprism can provide BPJabInstaller-1.0.2.exe which can install various versions of JAB where the version of the JRE does not have JAB bundled with it.

When JAB is bundled with the java installer it has to be enabled this can be done using the following command line. Open a command prompt and change to the java bin directory. e.g C:\Program Files\Java\Jre7\bin Then run the following command:

jabswitch.exe /enable

JAB can also be enabled with the Windows Ease of Access control panel (which can be activated by pressing Windows + U). The Ease of Access control panel has a Java Access Bridge checkbox.

The spy tool doesn't recognise elements

If the spy tool does not seem to recognise elements as you hover over them, check the following common causes first: a) failing to reboot after installing Java Access Bridge, b) using the wrong Java Access Bridge version

Attempting to write to a text box gives an error message

An error message such as 'Call to setTextContents failed. This method is known not to work against version 1.3.x of the Java Runtime Environment' indicates that you are trying to write to a Java text box in an application running under JRE 1.3. Unfortunately, this is impossible due to a missing implementation in the Java Access Bridge connectors that correspond to that JRE version.

In all cases there is a workaround, though some thought and ingenuity may be required on the part of the user. Here is a list of suggested workarounds for common problems:

General workaround – upgrade the Java Runtime Environment (JRE)

In most cases your target application should continue to function exactly as before following an upgrade, but you should consider the associated risk of any potential problems before doing so. Blue Prism will function reliably against version 1.4.0 or greater.

To work around a writing problem

If you are having a problem writing data to an element, you may send keystrokes to the application instead. This involves activating the window containing the element of interest, focusing the element ready to receive keyboard input, and using a Navigate stage to send keystrokes. Such keystrokes may need to include backspace or delete in order to clear any existing data in the element.

Accessing elements is very slow

There are some specific performance tips available for Java Access Bridge.