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 Java automation in 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 available JAB version for the installed JRE. From JRE7 onwards, JAB is provided with JRE and can be enabled via the Control Panel.

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

Blue Prism 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. Open a command prompt and change to the Java bin directory, for example, C:\Program Files\Java\Jre7\bin. Then run the following command:

jabswitch.exe /enable

JAB can also be enabled in Control Panel as follows:

1. Open Control Panel.
2. Select Ease of Access Center.
3. Select Make it easier to focus on tasks.
4. In the Other programs installed section, enable the setting Enable Java Access Bridge.
5. Click OK.

The spy tool doesn't recognize elements

If the spy tool does not seem to recognize elements as you hover over them, check the following common causes first:

• Failing to reboot after installing JAB.
• Using the wrong JAB version.

Attempting to write to a text box triggers 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. This is impossible due to a missing implementation in the JAB connectors that correspond to that JRE version.

Below is a list of suggested workarounds for common problems:

General workaround – Upgrade 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 JAB.

For more information, see Java automation.