Id must be assignable to Serializable error with 4.1.3

[ssherwood]

Per previous conversation about this issue started here: spring-projects/spring-boot#6709

When upgrading to Spring Boot 1.4.1 our projects started generating errors:

{"cause":null,"message":"Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable"}

Reverting back to Boot 1.4.0 reverted to expected behavior. It appears this is some kind of regression introduced in 4.1.3 as that is the default version in 1.4.1.

A simple project with the error is here: https://github.com/ssherwood/demo-neo4j

[mangrish]

Hi @ssherwood.

I will take a look soon. In the mean time can you try 4.2.0.BUILD-SNAPSHOT and see if your problem persists. You can see an example on how to use the snapshot with Spring Boot 1.4.1 here: https://github.com/neo4j-examples/sdn4-university/tree/4.2.x.

[ssherwood]

@mangrish I'm trying to emulate your work but I'm getting a new error:

org.springframework.beans.factory.BeanDefinitionStoreException: Failed to process import candidates for configuration class [com.example.DemoNeo4jApplication]; nested exception is java.io.FileNotFoundException: class path resource [org/springframework/data/neo4j/config/Neo4jConfiguration.class] cannot be opened because it does not exist

I'm not sure what might be at issue (it might be my environment since I'm working behind a proxy and have to jump through hoops to get at SNAPSHOTS). I'll commit my code to https://github.com/ssherwood/demo-neo4j and try from home to be sure.

[vince-bickers]

@ssherwood Did you manage to resolve this problem?

[ssherwood]

@vince-bickers No. I've tried a lot of things so far and have not had any succees unless I revert entirely back to Spring Boot 1.4.0. I'm doing these builds at home now and am running inside IntelliJ with a clean repo, so I can rule out a lot of environmental causes.

For me, the Ingalls-BUILD-SNAPSHOT seems to be missing the Neo4jConfiguration class:

java.io.FileNotFoundException: class path resource [org/springframework/data/neo4j/config/Neo4jConfiguration.class] cannot be opened because it does not exist

I noticed that the sdn4-university provides its own Neo4jConfiguration class which seems to be defeating the purpose of using Spring Boot's autoconfig approach. I suspect this is why your examples are not experiencing the same problem.

When I switch to Hopper-SR4, the config class returns and I can actually start up the application but the serialization error returns:

{"cause":null,"message":"Id must be assignable to Serializable! Object of class [null] must be an instance of interface java.io.Serializable"}

Interestingly, the nodes actually get created in Neo4j but I can view them with the Spring Data Rest interfaces.

[tigrou83]

I have the same problem than ssherwood with spring boot 1.4.2.RELEASE and spring-data-neo4j 4.2.0-SNAPSHOT:

org.springframework.beans.factory.BeanDefinitionStoreException: **Failed to process import candidates for configuration class [com.nagra.ml.sp.cpm.core.CpmNeo4jConfiguration]**; nested exception is java.io.FileNotFoundException: class path resource [org/springframework/data/neo4j/config/Neo4jConfiguration.class] cannot be opened because it does not exist
    at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:541)
...
**Caused by: java.io.FileNotFoundException: class path resource [org/springframework/data/neo4j/config/Neo4jConfiguration.class] cannot be opened because it does not exist**
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:172)
    at org.springframework.core.type.classreading.SimpleMetadataReader.<init>(SimpleMetadataReader.java:50)
    at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:98)
    at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.createMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:89)
    at org.springframework.boot.type.classreading.ConcurrentReferenceCachingMetadataReaderFactory.getMetadataReader(ConcurrentReferenceCachingMetadataReaderFactory.java:76)
    at org.springframework.core.type.classreading.SimpleMetadataReaderFactory.getMetadataReader(SimpleMetadataReaderFactory.java:93)
    at org.springframework.context.annotation.ConfigurationClassParser.asSourceClass(ConfigurationClassParser.java:633)
    at org.springframework.context.annotation.ConfigurationClassParser$SourceClass.getSuperClass(ConfigurationClassParser.java:796)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:308)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:230)
    at org.springframework.context.annotation.ConfigurationClassParser.processMemberClasses(ConfigurationClassParser.java:329)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:247)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:230)
    at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:532)
    ... 23 common frames omitted

[kbastani]

This issue looks to be resolved after this commit from @luanne 3c26a64

I ran into the same issue. The cause was due to a bug when checking whether or not an ID field was either an enum or a simple type. The bug was introduced with this commit: 37179a3. This was diagnosed by @xenoterracide in this comment: spring-projects/spring-boot#6709 (comment)

There is an issue at the moment when trying to use the 4.2.0.BUILD-SNAPSHOT with any Spring Boot release <= 1.4.3. The Spring Boot auto-configuration project is dependent on scanning for the Neo4jConfiguration class when spring-data-neo4j is found on the classpath of the application. Since the Neo4jConfiguration class was removed in the latest 4.2.0.BUILD-SNAPSHOT, the class loader for Spring Boot will not be able to find the Neo4jConfiguration file at the expected location org/springframework/data/neo4j/config/Neo4jConfiguration.java.

This bug will need to be fixed in the Spring Boot auto-configuration project.

Since I do not have the history on why Neo4jConfiguration was removed, I think it's best that @luanne or @mangrish raise this issue against https://github.com/spring-projects/spring-boot/blob/master/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/data/neo4j/Neo4jDataAutoConfiguration.java#L36

Spring Data Neo4j will continue to be broken for applications using Spring Data REST repositories until this is resolved. There is no workaround in the meantime.

/cc @philwebb @snicoll

[mangrish]

Moved to: https://jira.spring.io/browse/DATAGRAPH-955