Can't run job a second time if empty list is passed as parameter the first time (Oracle)

[nyg]

Bug description
When a job has a parameter of type java.util.List and the job is run with an empty list and the database is Oracle, it is not possible to run the job a second time.

The exception java.lang.IllegalArgumentException: value must not be null will be thrown by JobParameter because it is trying to convert null into a List. The null values comes from the fact that empty strings are the same thing as null for Oracle database (the empty string being the serialised empty list).

Environment

• Spring Batch 5.0.2
• Java 17
• Oracle database

Steps to reproduce

1. Create a job with a parameter of type List
2. Run the job with an empty list as argument
3. Run the job a second time (with any value as argument)

Expected behavior
It should be possible to run such a job an infinite number of times.

Minimal Complete Reproducible example
https://git.sr.ht/~nyg/example-java-spring-batch-bug

[weikangchia]

Hi @nyg , I am facing this issue also and would like to check if you have found any workaround?

[nyg]

Hello @weikangchia, the only workaround I found was to prevent null values from being given as parameters to a job...

[weikangchia]

I see same too! Thanks for sharing.

[nyg]

Hello @fmbenhassine, can you tell us if a fix is planned? Thanks a lot!

[fmbenhassine]

This seems specific to Oracle, as reported (I tested a couple other databases and the issue does not happen).

I am not an Oracle expert, but is there a way to tell Oracle to keep empty strings as empty strings and not persist them as null? I am not sure how Spring Batch can detect that case when deserializing job parameters.

That said, what's the point of using an empty list as a job parameter? Is there a valid use case I am missing?

[nyg]

Our use case is that we pass two lists of "internal" and "external" provider names. We then perform different actions on these providers. Sometime one of the two can be empty if it is not wanted in the job result.