spring-projects / spring-projects/spring-data-relational

Not possible to persist arrays containing null as first (or only) element

Open
#2,215 0 comments 0 reactions 1 assignee View on GitHub

@schauder is already working on this.

Since Jul 1, 2026.

status: waiting-for-triage
Dominant language
Java
Stars
827
Forks
394
PR merge metrics
No merged PRs in 30d

Description

In older versions of spring-data-relational it was possible to map collections of simple types containing null to a db array column. But this no longer works when the first element is null. If any element except for the first is null, it works as expected. Specifically, this example:

data class Entity(
    @Id
    val id: UUID,
    val column: List<String?>, // text[] db column type
)

val entity = Entity(UUID.randomUUID(), listOf(null))
aggregateTemplate.insert(entity)

throws the following error:

Cannot invoke "Object.getClass()" because the return value of "java.util.List.get(int)" is null
java.lang.NullPointerException: Cannot invoke "Object.getClass()" because the return value of "java.util.List.get(int)" is null
	at org.springframework.data.relational.core.conversion.MappingRelationalConverter.writeCollection(MappingRelationalConverter.java:817)
	at org.springframework.data.relational.core.conversion.MappingRelationalConverter.getPotentiallyConvertedSimpleWrite(MappingRelationalConverter.java:743)
	at org.springframework.data.jdbc.core.convert.MappingJdbcConverter.getPotentiallyConvertedSimpleWrite(MappingJdbcConverter.java:256)
	at org.springframework.data.relational.core.conversion.MappingRelationalConverter.writeValue(MappingRelationalConverter.java:721)
	at org.springframework.data.jdbc.core.convert.MappingJdbcConverter.writeJdbcValue(MappingJdbcConverter.java:294)
	at org.springframework.data.jdbc.core.convert.JdbcConverter.writeJdbcValue(JdbcConverter.java:50)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.addConvertedValue(SqlParametersFactory.java:244)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.addConvertedPropertyValue(SqlParametersFactory.java:231)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.lambda$getParameterSource$0(SqlParametersFactory.java:293)
	at org.springframework.data.mapping.model.BasicPersistentEntity.doWithProperties(BasicPersistentEntity.java:325)
	at org.springframework.data.mapping.PersistentEntity.doWithAll(PersistentEntity.java:270)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.getParameterSource(SqlParametersFactory.java:270)
	at org.springframework.data.jdbc.core.convert.SqlParametersFactory.forInsert(SqlParametersFactory.java:86)
	at org.springframework.data.jdbc.core.convert.DefaultDataAccessStrategy.insert(DefaultDataAccessStrategy.java:124)
	at org.springframework.data.jdbc.core.JdbcAggregateChangeExecutionContext.executeInsertRoot(JdbcAggregateChangeExecutionContext.java:82)
	at org.springframework.data.jdbc.core.AggregateChangeExecutor.execute(AggregateChangeExecutor.java:83)
	at org.springframework.data.jdbc.core.AggregateChangeExecutor.lambda$executeSave$0(AggregateChangeExecutor.java:60)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at org.springframework.data.relational.core.conversion.SaveBatchingAggregateChange.forEachAction(SaveBatchingAggregateChange.java:68)
	at org.springframework.data.jdbc.core.AggregateChangeExecutor.executeSave(AggregateChangeExecutor.java:60)
	at org.springframework.data.jdbc.core.JdbcAggregateTemplate.performSave(JdbcAggregateTemplate.java:590)
	at org.springframework.data.jdbc.core.JdbcAggregateTemplate.insert(JdbcAggregateTemplate.java:239)

This does not throw any error:

val entity = Entity(UUID.randomUUID(), listOf("a", null))
aggregateTemplate.insert(entity)

This issue appears to have been introduced by https://github.com/spring-projects/spring-data-relational/commit/068c957b140de26b09281de5a87915c703f1d0fd

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.