Eclipse Maven project reported "Unknown" error solution

Eclipse Maven project reported "Unknown" error solution

• 2019.7.23
• Copyright statement: This article is the original article of the blogger chszs, and shall not be reproduced without the permission of the blogger.

After creating a Maven project based on Spring Boot 2.1.6 with https://start.spring.io/, and importing the Eclipse 2019-03 (4.11.0) environment, an Unknown error is prompted . As shown below:

Unknown error points to the first line of pom.xml.

Even with the following means, the Unknown error persists:

1. Alt + F5 to update the project's pom
2. Clean + build operation in Eclipse
3. close/reopen project
4. Close project/delete project, reimport project
5. Close/reopen Eclipse
6. Delete the project and all Eclipse metadata, then reimport as a maven project

None of the above tricks worked. After analysis, this is a bug introduced by maven-jar-plugin 3.1.2, see https://bugs.eclipse.org/bugs/show_bug.cgi?id=547340 .

Simply downgrade maven-jar-plugin 3.1.2 to 3.1.1 in the project's pom.xml to eliminate the bug.

	<properties>
		<maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
	</properties>

Then Maven updates the project and the Unknown error disappears. As shown in the picture: