This plugin removes contraband items from players' inventories.
Specify the banned items in the properties file, for example:
#Fri Mar 23 21:14:06 EDT 2018
ITEMS=bedrock,command,structure
Be aware that the plugin does a case-insensitive substring compare. The above properties will ban players from posessing bedrock blocks, command blocks and structure blocks.
If, however, you said, for example:
ITEMS=bEd or ITEMS=BeD
The plugin will ban bedrock and beds. I don't think that's what you'd want. So think about what you code in the properties file, and maybe test it on your test server if you add new banned items.
Also, this plugin only affects normal players; OPs can have any item in the game, including command blocks, structure blocks, etc. regardless what you specify in the properties.
To install this plugin, copy the plugin JAR file to your server's plugins folder.