Currently, the Jackson2ExecutionContextStringSerializer fails to
deserialize json representations of:
* empty JobParameters instances due to the presence of "empty":true
in the serialized json String. In this case, Jackson is not able to find a
property named "empty" in the target type (JobParameters)
* JobParameter instances due to the presence of several constructors.
In this case, Jackson does not know which constructor to use.
This commit fixes these two issues by adding a custom Jackson module with:
* a mixin to ignore the "isEmpty" getter in JobParameters type
* a custom deserializer for JobParameter type
Resolves BATCH-2680
b0ffe55113