When configuring an MBean in a -service.xml file, or editing one through the JMX console, MBean attributes must be of types that return a valid PropertyEditor from the java.beans.PropertyManager.findEditor(Class) method.

JBoss registers several PropertyEditor classes for convenience and its own use.  Here is a list of the editors available in JBoss 4.0.3:

BigDecimalEditor
BlockingModeEditor - org.jboss.util.threadpool.BlockingMode
BooleanEditor
ByteArrayEditor - Uses String.getBytes
ByteEditor
CharacterEditor
ClassArrayEditor
ClassEditor
DateEditor - java.util.Date
DocumentEditor - org.w3c.dom.Document
DoubleEditor
ElementEditor - org.w3c.dom.Element
FileEditor - java.io.File
FloatEditor
InetAddressEditor - java.net.InetAddress
IntArrayEditor
IntegerEditor
LongEditor
PropertiesEditor - java.util.Properties
ShortEditor
StringArrayEditor
StringEditor
URIEditor - java.net.URI
URLEditor - java.net.URL

3.2 has a similar list.

You can add additional types using the java.beans.PropertyManager.registerEditor method or by creating a PropertyEditorManagerService MBean.