question: public final void renameClass ( Map classnames ) { String jvmNewThisName = ( String ) classnames . get ( Descriptor . toJvmName ( thisclassname ) ) ; if ( jvmNewThisName != null ) thisclassname = Descriptor . toJavaName ( jvmNewThisName ) ; constPool . renameClass ( classnames ) ; AttributeInfo . renameClass ( attributes , classnames ) ; ArrayList list = methods ; int n = list . size ( ) ; for ( int i = 0 ; i < n ; ++ i ) { MethodInfo minfo = ( MethodInfo ) list . get ( i ) ; String desc = minfo . getDescriptor ( ) ; minfo . setDescriptor ( Descriptor . rename ( desc , classnames ) ) ; AttributeInfo . renameClass ( minfo . getAttributes ( ) , classnames ) ; } list = fields ; n = list . size ( ) ; for ( int i = 0 ; i < n ; ++ i ) { FieldInfo finfo = ( FieldInfo ) list . get ( i ) ; String desc = finfo . getDescriptor ( ) ; finfo . setDescriptor ( Descriptor . rename ( desc , classnames ) ) ; AttributeInfo . renameClass ( finfo . getAttributes ( ) , classnames ) ; } }
target:  Replaces all occurrences of several class names in the class file.