In the FishEye's Administration > System Info page there is a line showing the Total Memory, which is the memory currently allocated by FishEye. Sometimes this causes confusion, because the Total Memory isn't actually what is defined as maximum heap (Xmx) but what is currently allocated, i.e. it may grow under demand (respecting the limit defined by the Xmx value).

This is the meaning for these values:

• Total memory shows the current size of the heap that the JVM used by FishEye is allocating. It does not reflect -Xmx. This heap can grow and shrink as needed, and varies according to what is defined as minimum (-Xms) and maximum (-Xmx) allowed heap.
• Free memory shows what is free from the current heap (total memory)

Maybe this information could go in https://confluence.atlassian.com/display/FISHEYE/How+FishEye+uses+memory.