The class is:
com.ptc.core.lwc.server.PersistableAdapter
The examples are the same:
CREATE
PersistableAdapter obj = new PersistableAdapter("com.acme.AcmePart",null,null);
obj.load("name","number");
obj.set("name","my name");
obj.set("number","12345");
obj.persist();
RETRIEVE
PersistableAdapter obj = new PersistableAdapter(my_persistable,null,null,null);
obj.load("name","number");
Object nameValue = obj.get("name");
Object numberValue = obj.get("number");
UPDATE
PersistableAdapter obj = new PersistableAdapter(my_persistable,null,Locale.US,new UpdateOperationIdentifier());
obj.load("attributeA","attribtueB");
obj.set("attributeA",Boolean.TRUE);
obj.set("attribtueB","PURPLE");
obj.apply();
...
PersistenceHelper.manager.modify(my_persistable);