A child container failed during start java.util.concurrent.ExecutionException [duplicate]

Answer 1

This issue might also be caused by a broken Maven repository.

I observe the SEVERE: A child container failed during start message from time to time when working with Eclipse. My Eclipse workspace has several projects. Some of the projects have common external dependencies. If Maven repository is empty (or I add new dependencies into pom.xml files), Eclipse starts downloading libraries specified in pom.xml into Maven repository. And Eclipse does that in parallel for several projects in the workspace. It might happen that several Eclipse threads would be downloading the same file simultaneously into the same place in Maven repository. As a result, this file becomes corrupted.

So, this is how you could resolve the issue.

1. Close your Eclipse.
2. If you know which specific jar-file is broken in Maven repository, then delete that file.
3. If you do not know which file is broken in Maven repository, then delete the whole repository (rm -rf $HOME/.m2).
4. For each project, run mvn package in the command line. It is important to run the command for each project one-by-one, not in parallel; thus, you ensure that only one instance of Maven runs each time.
5. Open your Eclipse.

Answer 2

I have observed a similar issue in my project. The issue was solved when the jar with the missing class definition was pasted into the lib directory of tomcat.