Sorry for the delayed answer but I haven't seen the question before in the general Java section.
The conversion of entities as parameters follow the basic principle of mapping in SDN e.g. a Player object might look like:
{
0: {__labels__: ["Player"], __id__: null, __properties__: {name: "player1"}},
testNode: {__labels__: ["Player"], __id__: null, __properties__: {name: "player1"}}
}
(The repetition with index based and named variable is due to the fact that we also support Spring Expression Language position-based parameters)
This means that you would have to add the __properties__ part in the query and as a result it would look like this:
@Query("MATCH (myPlayer:Player {name: $playerIn.__properties__.name}) RETURN myPlayer")
Player findPlayerByPlayer(@Param("playerIn") Player player);
There is a section in our documentation that does mention this in the example part: Custom query parameters
