Set Task CustomID as two strings concatenated

In a task event (event Queued) I want to concatenate two strings of Bussines Data to assign as Task CustomID. Like this:

#{currentTask.taskData.string1} + " - " + #{currentTask.taskData.string2}

But when the task is created, an exception is generated

Cannot convert the data type "java.lang.String" to "java.lang.Double"

It is possible with any other expression?

This operator works only for number types. It is not supported for strings and will generate an error when used with string values.

You can add a String type Data in Task Binding Services, make this Data equals string1+string2, and pick it in TaskCustomID field.

It is a limitation that forces you to go down to the code in the definition of the task rules but your solution works fine:
I have added a new String Data called “customID” to the Service container of Bindings palette and then added the following Java code to the getter method of the String:

	public java.lang.String getCustomID()  {
		String No, Description;
		Code = (String) resolveExpression("#{currentTask.taskData.Code}");
		Description = (String) resolveExpression("#{currentTask.taskData.Description}");
		customID = Code + " - " + Description;
		return customID;

Then, I can now use this value for assign the TaskCustomID.

Thank you very much.