diff --git a/.idea/misc.xml b/.idea/misc.xml
index f2f5415..ef40a45 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_16" project-jdk-name="16" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_15" project-jdk-name="15 (2)" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>
\ No newline at end of file
diff --git a/SpigotInvTweaks.iml b/SpigotInvTweaks.iml
index 347538c..c89e5fa 100644
--- a/SpigotInvTweaks.iml
+++ b/SpigotInvTweaks.iml
@@ -6,7 +6,7 @@
       <sourceFolder url="file://$MODULE_DIR$/res" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
     </content>
-    <orderEntry type="jdk" jdkName="16" jdkType="JavaSDK" />
+    <orderEntry type="jdk" jdkName="15 (2)" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="spigot-1.15.5-R0.1" level="project" />
   </component>
diff --git a/src/dev/w1zzrd/invtweaks/command/SearchCommandExecutor.java b/src/dev/w1zzrd/invtweaks/command/SearchCommandExecutor.java
index 9f48e7f..4d9edf0 100644
--- a/src/dev/w1zzrd/invtweaks/command/SearchCommandExecutor.java
+++ b/src/dev/w1zzrd/invtweaks/command/SearchCommandExecutor.java
@@ -98,7 +98,8 @@ public class SearchCommandExecutor extends ConfigurableCommandExecutor<SearchCon
             return true;
         }
 
-        if (result instanceof final DoubleChest dChest) {
+        if (result instanceof DoubleChest) {
+            final DoubleChest dChest = (DoubleChest) result;
 
             // Black magic to make chest lid animation behave for double chests
             try {
diff --git a/src/dev/w1zzrd/invtweaks/listener/StackReplaceListener.java b/src/dev/w1zzrd/invtweaks/listener/StackReplaceListener.java
index 5f1501b..c316ca6 100644
--- a/src/dev/w1zzrd/invtweaks/listener/StackReplaceListener.java
+++ b/src/dev/w1zzrd/invtweaks/listener/StackReplaceListener.java
@@ -56,9 +56,13 @@ public class StackReplaceListener implements Listener {
 
     @EventHandler
     public void onPlayerThrowSnowballEvent(final ProjectileLaunchEvent event) {
-        if (event.getEntity() instanceof final ThrowableProjectile projectile &&
-                projectile.getShooter() instanceof final Player thrower) {
+        if (event.getEntity() instanceof ThrowableProjectile &&
+                event.getEntity().getShooter() instanceof Player) {
 
+            final ThrowableProjectile projectile = (ThrowableProjectile) event.getEntity();
+            final Player thrower = (Player) event.getEntity().getShooter();
+
+            assert thrower != null;
             final PlayerInventory inventory = thrower.getInventory();
             final ItemStack stack = projectile.getItem();