Java thread dump: BLOCKED thread without “waiting to lock …”

Question

I\'m having difficulties in understanding the thread dump I got from jstack for a Spring MVC web application running on Tomcat 6 (java 1.6.0_22, Linux).

I see blocki

Answer 1

Apparently the situation where we observed these kinds of blocked threads were related to heavy memory consumption and therefore massive garbage collection.

This question Java blocking issue: Why would JVM block threads in many different classes/methods? describes a similar situation, so I believe these threads were simply blocked by the garbage collector.

(Anyway, after solving the memory issue this problem with the blocking threads was gone.)