Last week I wrote a blogpost about detecting multithreaded access on objects. To make it a little bit less abstract, you can find a report here (sorry for the lame file sharing mechanism). The report is created by running the tool on Apache Tomcat (a project with some concurrency problems).
In the first section you can find which fields are touched by multiple threads, and a few other statistics like the maximum number of read/writes by a single thread, and the maximum total number of read/writes by all threads on some instance. In the second report section you can see which instances were touched by which threads, and you can also see the overlapping fields (so fields touched by 2 or more threads).