proper logging

src/main/java/jetzt/nicht/minecraft/spigotSystemd/PluginListener.java

@@ -16,7 +16,6 @@ public class PluginListener implements Listener {
 
 	@EventHandler(priority = EventPriority.MONITOR)
 	public void onPluginEnabled(PluginEnableEvent event) {
-		System.out.println("Some plugin has been enabled!");
 		this.mainPlugin.onPluginEnabled();
 	}
 }

src/main/java/jetzt/nicht/minecraft/spigotSystemd/SpigotSystemdPlugin.java

 package jetzt.nicht.minecraft.spigotSystemd;
 
 import java.util.List;
+import java.util.logging.Logger;
 import org.bukkit.event.HandlerList;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -11,11 +12,15 @@ import jetzt.nicht.minecraft.spigotSystemd.PluginListener;
 import jetzt.nicht.minecraft.spigotSystemd.StartupListener;
 
 public class SpigotSystemdPlugin extends JavaPlugin {
-	PluginListener pluginListener;
-	StartupListener startupListener;
+	private PluginListener pluginListener;
+	private StartupListener startupListener;
+	private Logger log;
 
 	@Override
 	public void onEnable() {
+		// First of all, get a logger.
+		this.log = getLogger();
+
 		// When the plugin is being enabled, the server might just be starting,
 		// or the plugin is being reloaded, or the plugin is loaded late. We
 		// only want to start the whole readiness-listener-thing if the server
@@ -26,7 +31,7 @@ public class SpigotSystemdPlugin extends JavaPlugin {
 		// started if they are. At the very least this prevents us from
 		// registering a StartupListener if ALL the worlds have been loaded.
 		if (someWorldIsLoaded()) {
-			System.out.println("The server has already loaded a world! This " +
+			log.warning("The server has already loaded a world! This " +
 					"either means that the server/plugin has been reloaded, " +
 					"or the plugin has somehow been loaded late " +
 					"(please don't do that).");
@@ -35,7 +40,7 @@ public class SpigotSystemdPlugin extends JavaPlugin {
 			// Register our listener that waits for the server to be "ready".
 			// We pass in a reference to ourselves so the listener can call back.
 			this.startupListener = new StartupListener(this);
-			System.out.println("Registering StartupListener...");
+			log.finer("Registering StartupListener...");
 			getServer().getPluginManager()
 				.registerEvents(this.startupListener, this);
 			SDNotify.sendStatus("Starting...");
@@ -53,17 +58,22 @@ public class SpigotSystemdPlugin extends JavaPlugin {
 		// being activated again, if we implement watchdog functionality.
 	}
 
+	void onWorldInitialized() {
+		log.finer("Some World has been initialized!");
+		this.onServerMostlyReady();
+	}
+
 	void onServerMostlyReady() {
-		System.out.println("The server is now \"mostly ready\"!");
+		log.fine("The server is now \"mostly ready\"!");
 
 		// Unregister the StartupListener, as the server is now
 		// deemed "mostly ready"
-		System.out.println("Unregistering StartupListener...");
+		log.finer("Unregistering StartupListener...");
 		HandlerList.unregisterAll(this.startupListener);
 
 		// Register our listener that waits for plugins to be enabled. See above.
 		this.pluginListener = new PluginListener(this);
-		System.out.println("Registering PluginListener...");
+		log.finer("Registering PluginListener...");
 		getServer().getPluginManager()
 			.registerEvents(this.pluginListener, this);
 
@@ -75,26 +85,25 @@ public class SpigotSystemdPlugin extends JavaPlugin {
 
 	void onPluginEnabled() {
 		if (allPluginsEnabled()) {
-			System.out.println("All plugins have been enabled!");
-			System.out.println("Unregistering PluginListener...");
+			log.fine("All plugins have been enabled!");
+			log.finer("Unregistering PluginListener...");
 			HandlerList.unregisterAll(this.pluginListener);
 
-			System.out.println("Signalling readiness to systemd...");
+			log.info("Signalling readiness to systemd...");
 			SDNotify.sendNotify();
 			SDNotify.sendStatus("Ready to accept connections!");
 		} else {
-			System.out.println("There are still plugins to be enabled, continuing...");
+			log.fine("There are still plugins to be enabled, continuing...");
 		}
 	}
 
 	private boolean allPluginsEnabled() {
-		System.out.println("Checking whether all plugins have been enabled...");
+		log.finer("Some plugin has been enabled!");
+		log.fine("Checking whether all plugins have been enabled...");
 		Plugin[] loadedPlugins = getServer().getPluginManager().getPlugins();
 		boolean allPluginsEnabled = true;
 		for (Plugin plugin : loadedPlugins) {
-			System.out.println(
-					String.format("%s: %b", plugin, plugin.isEnabled())
-					);
+			log.finest(String.format("%s: %b", plugin, plugin.isEnabled()));
 			if (plugin.isEnabled() == false) {
 				allPluginsEnabled = false;
 				break;

src/main/java/jetzt/nicht/minecraft/spigotSystemd/StartupListener.java

@@ -16,7 +16,6 @@ public class StartupListener implements Listener {
 
 	@EventHandler(priority = EventPriority.MONITOR)
 	public void onWorldInitialized(WorldInitEvent event) {
-		System.out.println("Some World has been initialized!");
-		this.mainPlugin.onServerMostlyReady();
+		this.mainPlugin.onWorldInitialized();
 	}
 }