1. A computer-implemented method, comprising: associating, to meter usage of a predefined plurality of interpreted programs on a data processing system, each one of the predefined plurality of interpreted programs with an indication of at least one reference sequence of interpreter actions that identify the interpreted program, where each interpreted program is executed under control of an interpreter within a separate runtime environment and the reference sequence of interpreter actions comprises a reference sequence of at least one interpreter class load operation and at least one of a file read operation, a port opening operation, and a socket use operation; monitoring, from within each runtime environment, an executed sequence of interpreter actions performed by the interpreter within that runtime environment, where the monitored executed sequence of interpreter actions comprises at least one executed interpreter class load operation and at least one of an executed file read operation, an executed port opening operation, and an executed socket use operation; comparing a portion of the monitored executed sequence of interpreter actions performed by each interpreter with a plurality of reference sequences of interpreter actions associated with the predefined plurality of interpreted programs; and detecting the usage of each of the predefined plurality of interpreted programs in response to a matching of the monitored executed sequence of interpreter actions with one of the associated at least one reference sequence of interpreter actions.