Unable to upload lambda demo

[gacchan100]

I've installed AWS Toolkit Eclipse 2.0.
Then I created AWS Lambda Java Project.
I tryed to upload the demo code as above.
"Right Click" on demo de -> "AWS Lambda" -> "Upload function to Lambda"
Set the region on previously created S3 backet region, and click "next".
Click the "Complete" botton.
After that, Error message display as above.

Failed to upload project to Lambda
com.amazonaws.eclipse.core.exceptions.AwsActionException
Unable to export project [HelloLambda] to jar file
Failed to create JAR. See details for additional information.

What can I do to resolve this problem?

Eclipse version is as follows.
Version: 2021-09 (4.21.0)
Build id: 20210910-1417

Eclipse toolkit version is as follows.
AWS Toolkit for Eclipse Core
2.3.1.v201807201743