diff --git a/src/main/java/world/bentobox/boxed/Boxed.java b/src/main/java/world/bentobox/boxed/Boxed.java
index ccdfd14..405166b 100644
--- a/src/main/java/world/bentobox/boxed/Boxed.java
+++ b/src/main/java/world/bentobox/boxed/Boxed.java
@@ -231,7 +231,7 @@ public class Boxed extends GameModeAddon {
         if (id != null && id.equals("delete")) {
             return delChunks;
         }
-        return worldName.endsWith("_nether") ? netherChunkGenerator : chunkGenerator;
+        return worldName.endsWith(NETHER) ? netherChunkGenerator : chunkGenerator;
     }
 
     @Override
diff --git a/src/main/java/world/bentobox/boxed/generators/AbstractBoxedBiomeGenerator.java b/src/main/java/world/bentobox/boxed/generators/AbstractBoxedBiomeGenerator.java
index 2539b13..c71927a 100644
--- a/src/main/java/world/bentobox/boxed/generators/AbstractBoxedBiomeGenerator.java
+++ b/src/main/java/world/bentobox/boxed/generators/AbstractBoxedBiomeGenerator.java
@@ -25,7 +25,7 @@ import world.bentobox.boxed.Boxed;
  * @author tastybento
  *
  */
-public abstract class AbstractBoxedBiomeGenerator implements BiomeGenerator {
+abstract class AbstractBoxedBiomeGenerator implements BiomeGenerator {
 
     private static final Map<Environment, String> ENV_MAP;
     static {
@@ -77,24 +77,25 @@ public abstract class AbstractBoxedBiomeGenerator implements BiomeGenerator {
 
     private SortedMap<Double, Biome> loadQuad(YamlConfiguration config, String string) {
         SortedMap<Double, Biome> result = new TreeMap<>();
-        if (config.contains(string)) {
-            for (String ring : config.getStringList(string)) {
-                String[] split = ring.split(":");
-                if (split.length == 2 && NumberUtils.isNumber(split[0])) {
-                    try {
-                        double d = Double.parseDouble(split[0]);
-                        Biome biome = Enums.getIfPresent(Biome.class, split[1].toUpperCase(Locale.ENGLISH)).orNull();
-                        if (biome == null) {
-                            addon.logError(split[1].toUpperCase(Locale.ENGLISH) + " is an unknown biome on this server.");
-                        } else {
-                            result.put(d, biome);
-                        }
-                    } catch(Exception e) {
-                        addon.logError(string + ": " + split[0] + " does not seem to be a double. For integers add a .0 to the end");
+        if (!config.contains(string)) {
+            return result;
+        }
+        for (String ring : config.getStringList(string)) {
+            String[] split = ring.split(":");
+            if (split.length == 2 && NumberUtils.isNumber(split[0])) {
+                try {
+                    double d = Double.parseDouble(split[0]);
+                    Biome biome = Enums.getIfPresent(Biome.class, split[1].toUpperCase(Locale.ENGLISH)).orNull();
+                    if (biome == null) {
+                        addon.logError(split[1].toUpperCase(Locale.ENGLISH) + " is an unknown biome on this server.");
+                    } else {
+                        result.put(d, biome);
                     }
-                } else {
-                    addon.logError(ring + " must be in the format ratio:biome where ratio is a double.");
+                } catch(Exception e) {
+                    addon.logError(string + ": " + split[0] + " does not seem to be a double. For integers add a .0 to the end");
                 }
+            } else {
+                addon.logError(ring + " must be in the format ratio:biome where ratio is a double.");
             }
         }
         return result;
diff --git a/src/main/java/world/bentobox/boxed/generators/NetherGenerator.java b/src/main/java/world/bentobox/boxed/generators/NetherGenerator.java
index b0f8b85..c140f68 100644
--- a/src/main/java/world/bentobox/boxed/generators/NetherGenerator.java
+++ b/src/main/java/world/bentobox/boxed/generators/NetherGenerator.java
@@ -23,7 +23,8 @@ import world.bentobox.boxed.Boxed;
  */
 public class NetherGenerator implements BaseNoiseGenerator {
 
-    private final BiomeNoise DEFAULT_NOISE = new BiomeNoise(10D, 0D, 2D);
+    private static final String NETHER_BIOMES = "nether.biomes";
+    private final BiomeNoise defaultNoise = new BiomeNoise(10D, 0D, 2D);
     private final NoiseGenerator mainNoiseGenerator;
     private final Boxed addon;
     private final YamlConfiguration config;
@@ -41,11 +42,11 @@ public class NetherGenerator implements BaseNoiseGenerator {
         }
         config = YamlConfiguration.loadConfiguration(biomeFile);
         biomeNoiseMap = new EnumMap<>(Biome.class);
-        if (config.isConfigurationSection("nether.biomes")) {
-            for (String key : config.getConfigurationSection("nether.biomes").getKeys(false)) {
-                double noiseScaleHorizontal = config.getDouble("nether.biomes." + key + ".scale", 10D);
-                double height = config.getDouble("nether.biomes." + key + ".height", 0D);
-                double noiseScaleVertical = config.getDouble("nether.biomes." + key + ".vscale", 2D);
+        if (config.isConfigurationSection(NETHER_BIOMES)) {
+            for (String key : config.getConfigurationSection(NETHER_BIOMES).getKeys(false)) {
+                double noiseScaleHorizontal = config.getDouble(NETHER_BIOMES + "." + key + ".scale", 10D);
+                double height = config.getDouble(NETHER_BIOMES + "." + key + ".height", 0D);
+                double noiseScaleVertical = config.getDouble(NETHER_BIOMES + "." + key + ".vscale", 2D);
                 Enums.getIfPresent(Biome.class, key).toJavaUtil()
                 .ifPresent(biome -> biomeNoiseMap.put(biome, new BiomeNoise(noiseScaleHorizontal, height, noiseScaleVertical)));
             }
@@ -92,7 +93,7 @@ public class NetherGenerator implements BaseNoiseGenerator {
             // edge of island
             biome = Biome.NETHER_WASTES;
         }
-        BiomeNoise bm = this.biomeNoiseMap.getOrDefault(biome, DEFAULT_NOISE);
+        BiomeNoise bm = this.biomeNoiseMap.getOrDefault(biome, defaultNoise);
         double x = ((((double)scaledX*4) % dist) / 4) / bm.noiseScaleHorizontal;
         double z = ((((double)scaledZ*4) % dist) / 4) / bm.noiseScaleHorizontal;
         for (int y = 0; y < 16; y++) {
diff --git a/src/main/java/world/bentobox/boxed/listeners/AdvancementListener.java b/src/main/java/world/bentobox/boxed/listeners/AdvancementListener.java
index a98a81d..eb2a303 100644
--- a/src/main/java/world/bentobox/boxed/listeners/AdvancementListener.java
+++ b/src/main/java/world/bentobox/boxed/listeners/AdvancementListener.java
@@ -235,6 +235,7 @@ public class AdvancementListener implements Listener {
                             user.getPlayer().setStatistic(s, m, 0);
                     }
                 }
+                break;
             case ITEM:
                 for (Material m: Material.values()) {
                     if (m.isItem() && !m.isLegacy()) {