The java.lang.instrument
package provides a
Java™ programming language API for tools to instrument Java
programming language applications -- for example, to monitor them
or collect performance information. Tools use
java.lang.instrument
to modify the class file that
defines a class -- generally, by inserting into the byte-code of
methods additional byte-code which will perform the
instrumentation.
java.lang.instrument
was introduced in JDK™
5.0.
java.lang.management
package - the monitoring and management package, often
useful with instrumentation.