For service task return values, is Serializable required?

[matt1]

I'm new to Activiti so please bear with me.

I was playing around with returning values from service tasks and then passing that value to the subsequent task, and I was only able to return a POJO and use it in the subsequent task if I implemented Serializable. (maybe I'm doing something wrong.)

So this worked

public class Claim implements Serializable {
    long claimId;
    DateTime created;
…
‍‍‍‍‍

But this causes some type of serialization exception:

public class Claim {
    long claimId;
    DateTime created;
…
‍‍‍‍‍

More specifically I was using return value from task1 and passing it as an argument to task2, in both cases using Expressions.

task1 expression

#{prepareClaim()}‍

(return value set to 'claim')

task 2 expression

${claimService.create(claim)}‍

If Serializable is required, my question would then be why?

BTW, still not sure when to use

$‍

vs

#‍

[jbarrez]

If you do it like that, the values will be serialized to the database as java pojos. So yes, in that case these classes must be Serializable.

[matt1]

>If you do it like that
Is there another way? What is the best practice?

[trademak]

If you need the values in another task, you need to set multiple primitive values or you can serialize the full value as a Java object or change it JSON or XML.

Best regards,