Moved Nether goo to the appropriate package (+ more annotations)

src/main/java/io/github/thebusybiscuit/slimefun4/api/geo/GEOResource.java

@@ -1,5 +1,7 @@
 package io.github.thebusybiscuit.slimefun4.api.geo;
 
+import javax.annotation.Nonnull;
+
 import org.bukkit.Chunk;
 import org.bukkit.Keyed;
 import org.bukkit.World;
@@ -43,7 +45,7 @@ public interface GEOResource extends Keyed {
      * 
      * @return The default supply found in a {@link Chunk} with the given {@link Biome}
      */
-    int getDefaultSupply(Environment environment, Biome biome);
+    int getDefaultSupply(@Nonnull Environment environment, @Nonnull Biome biome);
 
     /**
      * Returns how much the value may deviate from the default supply (positive only).
@@ -57,6 +59,7 @@ public interface GEOResource extends Keyed {
      * 
      * @return The name of this Resource
      */
+    @Nonnull
     String getName();
 
     /**
@@ -65,6 +68,7 @@ public interface GEOResource extends Keyed {
      * 
      * @return The {@link ItemStack} version of this Resource.
      */
+    @Nonnull
     ItemStack getItem();
 
     /**
@@ -90,7 +94,8 @@ public interface GEOResource extends Keyed {
      *            The {@link Player} to localize the name for.
      * @return The localized name for this {@link GEOResource}
      */
-    default String getName(Player p) {
+    @Nonnull
+    default String getName(@Nonnull Player p) {
         String name = SlimefunPlugin.getLocalization().getResourceString(p, "resources." + getKey().getNamespace() + "." + getKey().getKey());
         return name == null ? getName() : name;
     }

src/main/java/io/github/thebusybiscuit/slimefun4/core/multiblocks/MultiBlock.java

@@ -5,6 +5,9 @@ import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import org.apache.commons.lang.Validate;
 import org.bukkit.Material;
 import org.bukkit.Tag;
@@ -44,6 +47,7 @@ public class MultiBlock {
         }
     }
 
+    @Nonnull
     public static Set<Tag<Material>> getSupportedTags() {
         return SUPPORTED_TAGS;
     }
@@ -53,7 +57,7 @@ public class MultiBlock {
     private final BlockFace trigger;
     private final boolean isSymmetric;
 
-    public MultiBlock(SlimefunItem item, Material[] build, BlockFace trigger) {
+    public MultiBlock(@Nonnull SlimefunItem item, Material[] build, @Nonnull BlockFace trigger) {
         Validate.notNull(item, "A MultiBlock requires a SlimefunItem!");
 
         if (build == null || build.length != 9) {
@@ -70,18 +74,21 @@ public class MultiBlock {
         this.isSymmetric = isSymmetric(build);
     }
 
+    @Nonnull
     public SlimefunItem getSlimefunItem() {
         return item;
     }
 
-    private static boolean isSymmetric(Material[] blocks) {
+    private static boolean isSymmetric(@Nonnull Material[] blocks) {
         return blocks[0] == blocks[2] && blocks[3] == blocks[5] && blocks[6] == blocks[8];
     }
 
+    @Nonnull
     public Material[] getStructure() {
         return blocks;
     }
 
+    @Nonnull
     public BlockFace getTriggerBlock() {
         return trigger;
     }
@@ -112,7 +119,7 @@ public class MultiBlock {
         return Objects.hash(item.getID(), blocks, trigger, isSymmetric);
     }
 
-    private boolean compareBlocks(Material a, Material b) {
+    private boolean compareBlocks(Material a, @Nullable Material b) {
         if (b != null) {
 
             for (Tag<Material> tag : SUPPORTED_TAGS) {

src/main/java/io/github/thebusybiscuit/slimefun4/core/multiblocks/MultiBlockMachine.java

@@ -5,6 +5,7 @@ import java.util.Arrays;
 import java.util.List;
 
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 import org.apache.commons.lang.Validate;
 import org.bukkit.Material;
@@ -77,6 +78,7 @@ public abstract class MultiBlockMachine extends SlimefunItem implements NotPlace
         return displayRecipes;
     }
 
+    @Nonnull
     public MultiBlock getMultiBlock() {
         return multiblock;
     }
@@ -121,7 +123,9 @@ public abstract class MultiBlockMachine extends SlimefunItem implements NotPlace
 
                 return true;
             }
-            else return false;
+            else {
+                return false;
+            }
         };
     }
 
@@ -158,7 +162,8 @@ public abstract class MultiBlockMachine extends SlimefunItem implements NotPlace
         }
     }
 
-    protected Inventory findOutputChest(Block b, ItemStack output) {
+    @Nullable
+    protected Inventory findOutputChest(@Nonnull Block b, @Nonnull ItemStack output) {
         for (BlockFace face : outputFaces) {
             Block potentialOutput = b.getRelative(face);
 
@@ -183,6 +188,7 @@ public abstract class MultiBlockMachine extends SlimefunItem implements NotPlace
         return null;
     }
 
+    @Nonnull
     private static Material[] convertItemStacksToMaterial(ItemStack[] items) {
         List<Material> materials = new ArrayList<>();
 

src/main/java/io/github/thebusybiscuit/slimefun4/core/services/CustomTextureService.java

@@ -61,7 +61,7 @@ public class CustomTextureService {
         config.setDefaultValue("_UI_NEXT_INACTIVE", 0);
 
         for (SlimefunItem item : items) {
-            if (item != null && item.getID() != null) {
+            if (item != null) {
                 config.setDefaultValue(item.getID(), 0);
 
                 if (config.getInt(item.getID()) != 0) {

src/main/java/io/github/thebusybiscuit/slimefun4/core/services/LocalizationService.java

@@ -49,7 +49,7 @@ public class LocalizationService extends SlimefunLocalization implements Persist
     private final NamespacedKey languageKey;
     private final Language defaultLanguage;
 
-    public LocalizationService(SlimefunPlugin plugin, String prefix, String serverDefaultLanguage) {
+    public LocalizationService(@Nonnull SlimefunPlugin plugin, @Nullable String prefix, @Nullable String serverDefaultLanguage) {
         super(plugin);
 
         this.plugin = plugin;
@@ -102,17 +102,20 @@ public class LocalizationService extends SlimefunLocalization implements Persist
     }
 
     @Override
+    @Nonnull
     public NamespacedKey getKey() {
         return languageKey;
     }
 
     @Override
+    @Nullable
     public Language getLanguage(@Nonnull String id) {
         Validate.notNull(id, "The language id cannot be null");
         return languages.get(id);
     }
 
     @Override
+    @Nonnull
     public Collection<Language> getLanguages() {
         return languages.values();
     }

src/main/java/io/github/thebusybiscuit/slimefun4/core/services/PerWorldSettingsService.java

@@ -204,7 +204,7 @@ public class PerWorldSettingsService {
         Config config = getConfig(world);
 
         for (SlimefunItem item : SlimefunPlugin.getRegistry().getEnabledSlimefunItems()) {
-            if (item != null && item.getID() != null) {
+            if (item != null) {
                 String addon = item.getAddon().getName().toLowerCase(Locale.ROOT);
                 config.setValue(addon + '.' + item.getID(), !items.contains(item.getID()));
             }
@@ -245,7 +245,7 @@ public class PerWorldSettingsService {
 
     private void loadItemsFromWorldConfig(String worldName, Config config, Set<String> items) {
         for (SlimefunItem item : SlimefunPlugin.getRegistry().getEnabledSlimefunItems()) {
-            if (item != null && item.getID() != null) {
+            if (item != null) {
                 String addon = item.getAddon().getName().toLowerCase(Locale.ROOT);
                 config.setDefaultValue(addon + ".enabled", true);
                 config.setDefaultValue(addon + '.' + item.getID(), true);

src/main/java/io/github/thebusybiscuit/slimefun4/core/services/PermissionsService.java

@@ -40,7 +40,7 @@ public class PermissionsService {
 
     public void register(@Nonnull Iterable<SlimefunItem> items, boolean save) {
         for (SlimefunItem item : items) {
-            if (item != null && item.getID() != null) {
+            if (item != null) {
                 String path = item.getID() + ".permission";
 
                 config.setDefaultValue(path, "none");

src/main/java/io/github/thebusybiscuit/slimefun4/implementation/guide/RecipeChoiceTask.java

@@ -3,6 +3,8 @@ package io.github.thebusybiscuit.slimefun4.implementation.guide;
 import java.util.HashMap;
 import java.util.Map;
 
+import javax.annotation.Nonnull;
+
 import org.apache.commons.lang.Validate;
 import org.bukkit.Bukkit;
 import org.bukkit.Material;
@@ -39,18 +41,18 @@ class RecipeChoiceTask implements Runnable {
      * @param inv
      *            The {@link Inventory} to start this task for
      */
-    public void start(Inventory inv) {
+    public void start(@Nonnull Inventory inv) {
         Validate.notNull(inv, "Inventory must not be null");
         inventory = inv;
         id = Bukkit.getScheduler().runTaskTimerAsynchronously(SlimefunPlugin.instance(), this, 0, UPDATE_INTERVAL).getTaskId();
     }
 
-    public void add(int slot, MaterialChoice choice) {
+    public void add(int slot, @Nonnull MaterialChoice choice) {
         Validate.notNull(choice, "Cannot add a null RecipeChoice");
         iterators.put(slot, new LoopIterator<>(choice.getChoices()));
     }
 
-    public void add(int slot, Tag<Material> tag) {
+    public void add(int slot, @Nonnull Tag<Material> tag) {
         Validate.notNull(tag, "Cannot add a null Tag");
         iterators.put(slot, new LoopIterator<>(tag.getValues()));
     }

src/main/java/io/github/thebusybiscuit/slimefun4/implementation/items/misc/StrangeNetherGoo.java

@@ -1,4 +1,4 @@
-package io.github.thebusybiscuit.slimefun4.implementation.resources;
+package io.github.thebusybiscuit.slimefun4.implementation.items.misc;
 
 import org.bukkit.entity.Piglin;
 import org.bukkit.inventory.ItemStack;

src/main/java/io/github/thebusybiscuit/slimefun4/implementation/resources/SlimefunResource.java

@@ -1,5 +1,8 @@
 package io.github.thebusybiscuit.slimefun4.implementation.resources;
 
+import javax.annotation.Nonnull;
+import javax.annotation.ParametersAreNonnullByDefault;
+
 import org.apache.commons.lang.Validate;
 import org.bukkit.NamespacedKey;
 import org.bukkit.inventory.ItemStack;
@@ -15,6 +18,7 @@ abstract class SlimefunResource implements GEOResource {
     private final int maxDeviation;
     private final boolean geoMiner;
 
+    @ParametersAreNonnullByDefault
     SlimefunResource(String key, String defaultName, ItemStack item, int maxDeviation, boolean geoMiner) {
         Validate.notNull(key, "NamespacedKey cannot be null!");
         Validate.notNull(defaultName, "The default name cannot be null!");
@@ -28,16 +32,19 @@ abstract class SlimefunResource implements GEOResource {
     }
 
     @Override
+    @Nonnull
     public NamespacedKey getKey() {
         return key;
     }
 
     @Override
+    @Nonnull
     public String getName() {
         return defaultName;
     }
 
     @Override
+    @Nonnull
     public ItemStack getItem() {
         return item.clone();
     }

src/main/java/io/github/thebusybiscuit/slimefun4/implementation/setup/SlimefunItemSetup.java

@@ -3,6 +3,8 @@ package io.github.thebusybiscuit.slimefun4.implementation.setup;
 import java.util.ArrayList;
 import java.util.List;
 
+import javax.annotation.Nonnull;
+
 import org.bukkit.Material;
 import org.bukkit.NamespacedKey;
 import org.bukkit.inventory.ItemStack;
@@ -147,6 +149,7 @@ import io.github.thebusybiscuit.slimefun4.implementation.items.misc.BasicCircuit
 import io.github.thebusybiscuit.slimefun4.implementation.items.misc.CoolantCell;
 import io.github.thebusybiscuit.slimefun4.implementation.items.misc.OrganicFertilizer;
 import io.github.thebusybiscuit.slimefun4.implementation.items.misc.OrganicFood;
+import io.github.thebusybiscuit.slimefun4.implementation.items.misc.StrangeNetherGoo;
 import io.github.thebusybiscuit.slimefun4.implementation.items.misc.SyntheticEmerald;
 import io.github.thebusybiscuit.slimefun4.implementation.items.multiblocks.ArmorForge;
 import io.github.thebusybiscuit.slimefun4.implementation.items.multiblocks.AutomatedPanningMachine;
@@ -185,7 +188,6 @@ import io.github.thebusybiscuit.slimefun4.implementation.items.weapons.IcyBow;
 import io.github.thebusybiscuit.slimefun4.implementation.items.weapons.SeismicAxe;
 import io.github.thebusybiscuit.slimefun4.implementation.items.weapons.SwordOfBeheading;
 import io.github.thebusybiscuit.slimefun4.implementation.items.weapons.VampireBlade;
-import io.github.thebusybiscuit.slimefun4.implementation.resources.StrangeNetherGoo;
 import io.github.thebusybiscuit.slimefun4.utils.HeadTexture;
 import io.github.thebusybiscuit.slimefun4.utils.SlimefunUtils;
 import me.mrCookieSlime.Slimefun.Lists.RecipeType;
@@ -226,7 +228,7 @@ public final class SlimefunItemSetup {
 
     private SlimefunItemSetup() {}
 
-    public static void setup(SlimefunPlugin plugin) {
+    public static void setup(@Nonnull SlimefunPlugin plugin) {
         if (registeredItems) {
             throw new UnsupportedOperationException("Slimefun Items can only be registered once!");
         }

src/main/java/me/mrCookieSlime/Slimefun/api/SlimefunItemStack.java

@@ -8,6 +8,9 @@ import java.util.Locale;
 import java.util.Optional;
 import java.util.function.Consumer;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import org.apache.commons.lang.Validate;
 import org.bukkit.ChatColor;
 import org.bukkit.Color;
@@ -146,7 +149,7 @@ public class SlimefunItemStack extends CustomItem {
         setItemId(id);
     }
 
-    private void setItemId(String id) {
+    private void setItemId(@Nonnull String id) {
         Validate.notNull(id, "The Item id must never be null!");
         Validate.isTrue(id.equals(id.toUpperCase(Locale.ROOT)), "Slimefun Item Ids must be uppercase! (e.g. 'MY_ITEM_ID')");
 
@@ -169,7 +172,8 @@ public class SlimefunItemStack extends CustomItem {
      * 
      * @return The {@link SlimefunItem} id for this {@link SlimefunItemStack}
      */
-    public String getItemId() {
+    @Nonnull
+    public final String getItemId() {
         return id;
     }
 
@@ -179,6 +183,7 @@ public class SlimefunItemStack extends CustomItem {
      *
      * @return The {@link SlimefunItem} for this {@link SlimefunItemStack}, null if not found.
      */
+    @Nullable
     public SlimefunItem getItem() {
         return SlimefunItem.getByID(id);
     }
@@ -267,7 +272,11 @@ public class SlimefunItemStack extends CustomItem {
         return SkullItem.fromBase64(getTexture(id, texture));
     }
 
-    private static String getTexture(String id, String texture) {
+    @Nonnull
+    private static String getTexture(@Nonnull String id, @Nonnull String texture) {
+        Validate.notNull(id, "The id cannot be null");
+        Validate.notNull(texture, "The texture cannot be null");
+        
         if (texture.startsWith("ey")) {
             return texture;
         }