Jira 6.1.7 would not start after upgrading from 6.0.6

[Mikhail T]

Getting the following from catalina:

SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]
        at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source)
        at java.util.concurrent.FutureTask.get(Unknown Source)
....
Caused by: java.lang.NoClassDefFoundError: com/atlassian/jira/web/filters/JiraImportProgressFilter$SimpleTaskDescriptorBean
....

I can see the "missing" class-file right here:

./jira/atlassian-jira/WEB-INF/classes/com/atlassian/jira/web/filters/JiraImportProgressFilter$SimpleTaskDescriptorBean.class

why is it being reported as not found? Thank you!

[Mikhail T · Accepted solution]

Oh... Only after posting the question did it occur to me to ls the class file... It was not readable (to the jira-user). The silly installer put out a handful of classes with the mode of 640 (owned by root:root)...

After summarily chmod-ing every file to 644 I'm able to start Jira...