How do I resolve the "java.lang.ClassNotFoundException: com.example.package.resource.HandlerWrapper" error in AWS CloudFormation?
Last updated: 2020-08-17
I receive the "java.lang.ClassNotFoundException: com.example.package.resource.HandlerWrapper" error when I try to invoke my resource provider in AWS CloudFormation. How do I resolve this error?
Short description
You receive this error when you're developing or testing a resource provider schema and you call cfn test or sam local invoke, but the /target/ directory in your project doesn't contain a valid .jar file.
By default, the name of the .jar file is in the format organization-service-resource-handler-1.0-SNAPSHOT.jar and is configured in the pom.xml file in your project's root directory. For example:
<groupId>com.organization.service.resource</groupId>
<artifactId>organization-service-resource-handler</artifactId>
<name>organization-service-resource-handler</name>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>If you're having issues with other errors related to using a resource provider, see the following articles for additional troubleshooting steps:
- How do I resolve the "Resource specification is invalid" error when I run the cfn generate command using the CloudFormation CLI in AWS CloudFormation?
- How do I resolve the "Model validation failed (#: extraneous key [Key] is not permitted)" error in AWS CloudFormation?
- How do I resolve the "Resource timed out waiting for creation of physical resource" error when I create a resource using my resource provider type in AWS CloudFormation?
- How do I resolve the "Attribute 'Key' does not exist" error when I use the Fn::GetAtt function on my resource provider resource in AWS CloudFormation?
Resolution
1. To build your project, run cfn generate followed by mvn package. For example:
$ cfn generate
Generated files for Organization::Service::Resource
$ mvn package
[INFO] Scanning for projects...
[INFO]
[INFO] --< software.organization.service.resource:organization-service-resource-handler >--
[INFO] Building organization-service-resource-handler 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 21.690 s
[INFO] Finished at: 2020-07-14T16:02:47-05:00
[INFO] ------------------------------------------------------------------------Note: If the build and tests are successful, mvn creates the necessary .jar file in the /target/ directory.
2. If your unit tests aren't complete and you want to skip the tests, run mvn -Dmaven.test.skip=true package instead of mvn package.
$ cfn generate
Generated files for Organization::Service::Resource
$ mvn package -Dmaven.test.skip=true package
[INFO] Scanning for projects...
[INFO]
[INFO] --< software.organization.service.resource:organization-service-resource-handler >--
[INFO] Building organization-service-resource-handler 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 21.690 s
[INFO] Finished at: 2020-07-14T16:02:47-05:00
[INFO] ------------------------------------------------------------------------Tip: You can troubleshoot the tests by navigating to the directory /target/surefire-reports from your project's root directory.
Related information
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