Items in the droppers which created by the command block will not disappear but continue to reproduce itself

Use command block to spawn a dropper with item in its inventory.

/setblock ~ ~ ~5 minecraft:dropper 0 replace {Items:[{id:35,Damage:0,Slot:0}]}

The dropper drops an item from its inventory every time when powered.

However the "dropped item" in the inventory does not disappear but continue to reproduce itself.

This could make infinite items.