Sometimes I get a BeanCreationException when starting a Java Spring Boot single-JAR application built by Gradle. My investigations show that it depends on the JAR file and how it has been built by Gradle. Most often (but not always) I see the exception when I build the project on a Linux system. But I have never reproduced the issue with a JAR built on Windows or when running from IntelliJ Idea.
I tried to compare the content of a working JAR with the JAR throwing the exception - all the *.class files (including meta and resources) were binary equal, the only difference was in the order the files were stored in the JAR/ZIP archive. I also tried to unpack the failing JAR on Windows and just repack it into a new JAR file (using 7-zip) - the application started without any exceptions. This weird workaround solved the issue, but it's not something I'd like to do after each build on a linux machine.
The exception suggests to check circular references, so I tried replacing @Autowired properties with @Autowired bean constructors to help me to find the problem but that didn't help. The stacktrace does not mention any of my classes, so I don't know what bean could be responsible for the issue. And because of the fact the issue happens only sometimes and is solvable by repacking the JAR file, I'm not sure there are any circular references anyway.
Could you please help me? Any advice or suggestion is welcomed.
JDK: openjdk 8u262 Gradle version 5.6 Spring boot 2.3.1
Exception message:
BeanCreationException: Error creating bean with name 'webConfig':
Invocation of init method failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name 'requestMappingHandlerAdapter' defined in class path resource
[org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]:
Unsatisfied dependency expressed through method 'requestMappingHandlerAdapter' parameter 0;
nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException:
Error creating bean with name 'mvcContentNegotiationManager':
Requested bean is currently in creation: Is there an unresolvable circular reference?