JobStep Jackson2ExecutionContextStringSerializer error in Spring Batch 6.x

[andrianov17]

Bug description
After upgrade from Spring Batch 5.2.3 to Spring Batch 6.0.1 and preserving previous org.springframework.batch.core.repository.dao.Jackson2ExecutionContextStringSerializer serializer, JobStep fails with the exception:

Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not write a field name, expecting a value (through reference chain: java.util.HashMap["org.springframework.batch.core.step.job.JobStep.JOB_PARAMETERS"]->org.springframework.batch.core.job.parameters.JobParameters["parameters"]->java.util.Collections$UnmodifiableSet[0])
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:400)
	at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:371)
	at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:346)
	at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContentsUsing(CollectionSerializer.java:186)
	at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:120)
	at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:25)
	at com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase.serializeWithType(AsArraySerializerBase.java:265)
	at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:734)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:760)
	at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeWithType(BeanSerializerBase.java:643)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeTypedFields(MapSerializer.java:1026)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:778)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithoutTypeInfo(MapSerializer.java:763)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithType(MapSerializer.java:732)
	at com.fasterxml.jackson.databind.ser.std.MapSerializer.serializeWithType(MapSerializer.java:34)
	at com.fasterxml.jackson.databind.ser.impl.TypeWrappedSerializer.serialize(TypeWrappedSerializer.java:32)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:503)
	at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:342)
	at com.fasterxml.jackson.databind.ObjectMapper._writeValueAndClose(ObjectMapper.java:4926)
	at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:4105)
	at org.springframework.batch.core.repository.dao.Jackson2ExecutionContextStringSerializer.serialize(Jackson2ExecutionContextStringSerializer.java:165)
	at org.springframework.batch.core.repository.dao.Jackson2ExecutionContextStringSerializer.serialize(Jackson2ExecutionContextStringSerializer.java:114)
	at org.springframework.batch.core.repository.dao.jdbc.JdbcExecutionContextDao.serializeContext(JdbcExecutionContextDao.java:361)
	... 28 more
Caused by: com.fasterxml.jackson.core.JsonGenerationException: Can not write a field name, expecting a value
	at com.fasterxml.jackson.core.JsonGenerator._constructWriteException(JsonGenerator.java:2937)
	at com.fasterxml.jackson.core.JsonGenerator._reportError(JsonGenerator.java:2921)
	at com.fasterxml.jackson.core.json.UTF8JsonGenerator.writeFieldName(UTF8JsonGenerator.java:217)
	at org.springframework.batch.core.repository.dao.Jackson2ExecutionContextStringSerializer$JobParametersModule$JobParameterSerializer.serialize(Jackson2ExecutionContextStringSerializer.java:213)
	at org.springframework.batch.core.repository.dao.Jackson2ExecutionContextStringSerializer$JobParametersModule$JobParameterSerializer.serialize(Jackson2ExecutionContextStringSerializer.java:195)
	at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContentsUsing(CollectionSerializer.java:179)
	... 49 more

Upon debugging, it fails trying to serialize the first JobParameter.

Environment
Spring Batch 6.0.1, SQL Server 2022

Steps to reproduce

• Have a job using JobStep step
• Run the job passing some parameters to it

Expected behavior
Job runs successfully, saving step execution context like this (as it was in 5.2.3):

{
	"@class": "java.util.HashMap",
	"childJobExecId": [
		"java.lang.Long",
		3480
	],
	"org.springframework.batch.core.step.job.JobStep.JOB_PARAMETERS": {
		"@class": "org.springframework.batch.core.JobParameters",
		"parameters": {
			"@class": "java.util.Collections$UnmodifiableMap",
			"queueItemId": {
				"@class": "org.springframework.batch.core.JobParameter",
				"value": "250702",
				"type": "java.lang.String",
				"identifying": false
			},
			"execType": {
				"@class": "org.springframework.batch.core.JobParameter",
				"value": "MANUAL",
				"type": "java.lang.String",
				"identifying": false
			},
			"user": {
				"@class": "org.springframework.batch.core.JobParameter",
				"value": "system",
				"type": "java.lang.String",
				"identifying": false
			}
		}
	},
	"batch.version": "5.2.3"
}

Please also notice that org.springframework.batch.core.repository.dao.Jackson2ExecutionContextStringSerializer.JobParametersModule.JobParameterSerializer#serialize is not adjusted to serialize parameter name.

Minimal Complete Reproducible example
Pretty straightforward - see steps to reproduce above