code: static public void initFromSystemProperties(Object o, Properties prop) {
          updateFieldsFromProperties(o.getClass(), o, prop);
      }
docs: /*
  initFromProperties - initializes fields (static and non-static) in an Object based
  on system properties.  For example, given Object o of class com.company.Foo
  with field cacheSize. The following system property would change the field
  -Dcom.company.Foo.cacheSize=100