You can unload classes into an image component without unloading containing applications. To do this, you use the method dumpClasses: contained in ApplicationDumper. It unloads classes along with their class variables, class instance variables, and shared pool variables. Unless you specify values for the variables, it assigns nil to the values upon unload.

You must be careful when transferring classes that contain references to operating system resources such as graphics resources, file handles, or process handles. Upon unload, ENVY/App might replace instances of these classes with nil, making the references undefined. After the components are unloaded and reloaded, you must verify that the newly loaded code properly reinitializes all references to operating system resources.

Three examples illustrate how to unload classes

Prior to executing the code in any of these examples, load packaging instructions and create an instance of EaComponentMapManager called ComponentMaps by executing Step 1 of Example: Unloading an application and its subapplications.

To unload the class String into an image component file, you evaluate the code below.

To unload the class Number and its subclasses into an image component file, you evaluate:

To unload the both String and Number (with its subclasses) into image component files, evaluate:

Note that the effects of using dumpClasses: are cumulative, persist between unloading operations, and cannot be undone. The code's second use of dumpClasses: unloads both String and Number into a file. To remove a class from a file, you must create a new instance of ApplicationDumper and unload the classes you want into the file.