| Package | Description | 
|---|---|
| java.lang.instrument | Provides services that allow Java programming language agents to instrument programs running on the JVM. | 
| Class and Description | 
|---|
| ClassDefinition This class serves as a parameter block to the  Instrumentation.redefineClassesmethod. | 
| ClassFileTransformer An agent provides an implementation of this interface in order
 to transform class files. | 
| IllegalClassFormatException Thrown by an implementation of
  ClassFileTransformer.transformwhen its input parameters are invalid. | 
| UnmodifiableClassException Thrown by an implementation of
  Instrumentation.redefineClasseswhen one of the specified classes cannot be modified. | 
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