Version Sources and Comparison

Constructors (where “latest” comes from)

Constructor	Remote “latest”
PluginUpdateChecker(JavaPlugin, String githubOwnerRepo)	GitHub Releases API: tag_name of the first release in the array. Empty array → IOException (“no GitHub release found”).
PluginUpdateChecker(JavaPlugin, URL plainTextVersionUrl)	HTTP GET; first non-empty line after trim.
PluginUpdateChecker(JavaPlugin, RemoteVersionSupplier)	Your code; may throw IOException. Must not use the Bukkit API (runs on an async thread).

Built-in HTTP uses HttpURLConnection with the User-Agent and connect timeout you configure on the checker (see Checks, scheduler, and HTTP).

Installed version

• Read from plugin.getDescription().getVersion() (trimmed) unless you call setInstalledVersion(String); null clears the override.

Ordering and sanity filter

• Ordering: Maven-style via org.apache.maven.artifact.versioning.ComparableVersion (segments and qualifiers, not plain lexicographic string order).
• Sanity filter: If the remote string is not strictly newer than installed, the outcome is running latest (avoids false “update” from odd API data).

Static helper

• PluginUpdateChecker.isRemoteVersionNewer(String installed, String remote) - true only if remote compares strictly newer than installed.

Equivalent logic: VersionCompare.isRemoteNewerThanInstalled.