java.lang.instrumentpackage provides a JavaTM programming language API for tools to instrument Java programming language applications -- for example, to monitor them or collect performance information. Tools use
java.lang.instrumentto 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.instrumentwas introduced at JDKTM 5.0.
java.lang.managementpackage - the monitoring and management package, often useful with instrumentation.