Loads a map of field names -> byte arrays from a standard compiled Java class
but uses a temporary ClassLoader so that its class may be immediately unloaded
from the JVM and it's memory + constant pool can be used for other things.
This class provides an empty implementation of RockerParserListener,
which can be extended to create a listener which only needs to handle a subset
of the available methods.
This class provides an empty implementation of WithBlockParserListener,
which can be extended to create a listener which only needs to handle a subset
of the available methods.