The Java Dynamic Management Kit (JDMK), developed by Sun Microsystems [#!jdmk-wp!#,#!jdmk-v30!#], promises to overcome many of the problems mentioned and supports some new requirements. Application Response Measurement API (ARM) is a valuable standard for the application perfomance instrumentation. In the next sections, we will introduce the architecture and services of JDMK and the concepts and use of ARM.