Code improvements

src/main/java/me/lortseam/completeconfig/ConfigBuilder.java

@@ -50,6 +50,7 @@ public final class ConfigBuilder {
      * @return this config builder
      */
     public ConfigBuilder add(ConfigGroup... groups) {
+        Arrays.stream(groups).forEach(Objects::requireNonNull);
         topLevelGroups.addAll(Arrays.asList(groups));
         return this;
     }

src/main/java/me/lortseam/completeconfig/ConfigHandler.java

@@ -13,11 +13,11 @@ import java.util.Set;
 
 public final class ConfigHandler {
 
-    private static final Set<ConfigHandler> HANDLERS = new HashSet<>();
+    private static final Set<ConfigHandler> handlers = new HashSet<>();
 
     static {
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
-            for (ConfigHandler handler : HANDLERS) {
+            for (ConfigHandler handler : handlers) {
                 handler.save();
             }
         }));
@@ -31,7 +31,7 @@ public final class ConfigHandler {
         this.source = source;
         config = new Config(source.getModID(), topLevelGroups);
         this.guiBuilder = guiBuilder;
-        HANDLERS.add(this);
+        handlers.add(this);
         source.load(config);
     }
 

src/main/java/me/lortseam/completeconfig/ConfigSource.java

@@ -23,7 +23,7 @@ import java.util.Set;
 final class ConfigSource {
 
     private static final Logger LOGGER = LogManager.getLogger();
-    private static final Set<ConfigSource> SOURCES = new HashSet<>();
+    private static final Set<ConfigSource> sources = new HashSet<>();
     private static TypeSerializerCollection globalTypeSerializers;
 
     static void registerGlobalTypeSerializers(TypeSerializerCollection typeSerializers) {
@@ -38,7 +38,7 @@ final class ConfigSource {
     ConfigSource(String modID, String[] branch, TypeSerializerCollection typeSerializers) {
         this.modID = modID;
         this.branch = branch;
-        if (!SOURCES.add(this)) {
+        if (!sources.add(this)) {
             throw new IllegalArgumentException("A config of the mod " + modID + " with the specified branch " + Arrays.toString(branch) + " already exists!");
         }
         String[] subPath = ArrayUtils.add(branch, 0, modID);

src/main/java/me/lortseam/completeconfig/data/Entry.java

@@ -23,7 +23,7 @@ import java.util.function.Consumer;
 public class Entry<T> extends EntryBase<T> implements DataPart {
 
     private static final Logger LOGGER = LogManager.getLogger();
-    private static final Map<Field, EntryBase> ENTRIES = new HashMap<>();
+    private static final Map<Field, EntryBase> entries = new HashMap<>();
 
     static EntryBase<?> of(String fieldName, Class<? extends ConfigEntryContainer> parentClass) {
         try {
@@ -34,7 +34,7 @@ public class Entry<T> extends EntryBase<T> implements DataPart {
     }
 
     static EntryBase<?> of(Field field) {
-        return ENTRIES.computeIfAbsent(field, absentField -> new Draft<>(field));
+        return entries.computeIfAbsent(field, absentField -> new Draft<>(field));
     }
 
     private final ConfigEntryContainer parentObject;
@@ -273,7 +273,7 @@ public class Entry<T> extends EntryBase<T> implements DataPart {
             for (Consumer<Entry<T>> interaction : interactions) {
                 interaction.accept(entry);
             }
-            ENTRIES.put(field, entry);
+            entries.put(field, entry);
             return entry;
         }