Here's an online tool, no installation required:
http://spotify.github.io/threaddump-analyzer/
I wrote it since I was also missing this.
Question
I often use Java Thread Dumps for post-mortems and server slowdown analysis. The problem is that the thread dumps are often long, and understanding the concurrency relationship between the threads might be tedious.
Is there a (preferably online) tool that can parse a Java Thread Dump and show a humen-readable summary?
La solution
Here's an online tool, no installation required:
http://spotify.github.io/threaddump-analyzer/
I wrote it since I was also missing this.
Autres conseils
IntelliJ (either Community Edition or Ultimate Edition) has a nice Stacktrace/Thread Dump analyzer.
It is not an online tool but you said preferably online so this is an adequate answer IMO.