UseBlockCallback called multiple times for one click

UseBlockCallback.EVENT.register((player, world, hand, hitResult) -> {
            System.out.println("hit thing");
});

If I right click a block with an empty hand, this is printed out 4 times. If I place a block, this is printed 2 times. I’m using 19w07a.

[flier268]

How do I know that who call UseBlockCallback? (client or server)

world.isClient() will return true if it is on the client, and false on the server.

Thanks a lot

[Blayyke]

How do I know that who call UseBlockCallback? (client or server)

world.isClient() will return true if it is on the client, and false on the server.