Bukkit2Sponge allows loading SpongeAPI plugins on Bukkit servers. An unofficial alternative to running the fully-fledged Sponge or SpongeVanilla servers.
Warning: very incomplete (bug reports and pull requests appreciated, see issues for implementation progress). As of 0.0.1, only simple test plugins work.
Copy the plugin jar to the plugins directory of your Bukkit server.
Run your server, the first time it will create a plugins/Bukkit2Sponge/plugins/ directory. You can place your SpongeAPI plugins here.
If using the Glowstone++ server, you can alternatively place the SpongeAPI plugins in the top-level plugins/ directory and they will be loaded by Bukkit2Sponge as well (requires build 226+).
When starting the server, if configured correctly Bukkit2Sponge should log the SpongeAPI plugins it finds:
17:52:00 [INFO] [Bukkit2Sponge] Loading plugins...
17:52:00 [INFO] [Bukkit2Sponge] Initializing 2 SpongeAPI plugins...