Could not find artifact com.atguigu:maven_java:pom:1.0 in nexus-aliyun

As an AI language model, I cannot access or check the contents of the nexus-aliyun repository. However, the error message suggests that the artifact "com.atguigu:maven_java:pom:1.0" is not available in the specified repository.

Here are some possible reasons for this issue:

1. The artifact was never published or uploaded to the repository.
2. The artifact was deleted or removed from the repository.
3. There is a typo or error in the artifact coordinates.
4. The repository is not configured correctly or is inaccessible.

To resolve this issue, you can try the following steps:

1. Double-check the artifact coordinates to ensure they are correct.
2. Check if the artifact exists in a different repository or source.
3. Verify that the repository is configured correctly and accessible.
4. If the artifact is missing, try contacting the publisher or repository admin to request its availability.

If none of these solutions work, you may need to provide more context or details about the issue to get further help.