  We introduced a new approach to describe Java software as graph, where nodes
represent a Java file - called compilation unit (CU) - and an edges represent a
relations between them. The software system is characterized by the degree
distribution of the graph properties, like in-or-out links, as well as by the
distribution of Chidamber and Kemerer metrics computed on its CUs. Every CU can
be related to one or more bugs during its life. We find a relationship among
the software system and the bugs hitting its nodes. We found that the
distribution of some metrics, and the number of bugs per CU, exhibit a
power-law behavior in their tails, as well as the number of CUs influenced by a
specific bug. We examine the evolution of software metrics across different
releases to understand how relationships among CUs metrics and CUs faultness
change with time.
