Fix JDK12+ final field modification startup issues with java version …

…detection and a method from https://stackoverflow.com/questions/61141836/change-static-final-field-in-java-12

patches/api/0105-Fix-JDK12-final-field-modification-issues.patch

@@ -0,0 +1,65 @@
+From fa5d9f5884279a1dbbe301a165e5e769d64d82ff Mon Sep 17 00:00:00 2001
+From: Jason Ho <[email protected]>
+Date: Sat, 24 Aug 2024 23:00:45 -0700
+Subject: [PATCH] Fix JDK12+ final field modification issues
+
+
+diff --git a/src/main/java/app/ashcon/sportpaper/api/reflection/ReflectionUtils.java b/src/main/java/app/ashcon/sportpaper/api/reflection/ReflectionUtils.java
+new file mode 100644
+index 00000000..88b50515
+--- /dev/null
++++ b/src/main/java/app/ashcon/sportpaper/api/reflection/ReflectionUtils.java
+@@ -0,0 +1,50 @@
++package app.ashcon.sportpaper.api.reflection;
++
++import jdk.internal.misc.Unsafe;
++
++import java.lang.reflect.Field;
++import java.lang.reflect.Modifier;
++
++public class ReflectionUtils {
++
++    static final double JDK12 = 56.0;
++
++    public static Double getJavaVersion() {
++        String version = System.getProperty("java.class.version");
++        return Double.parseDouble(version);
++    }
++
++    public static void modifyFinal(Class<?> clazz, String fieldName, Object instance, Object value) throws Exception {
++        Double javaVersion = getJavaVersion();
++        if (javaVersion < JDK12) {
++            jdk8_modifyFinal(clazz, fieldName, instance, value);
++        } else {
++            try {
++                jdklatest_modifyFinal(clazz, fieldName, instance, value);
++            } catch(Exception e) {
++                throw new RuntimeException("ReflectionUtils: " +
++                        "Unsupported Java version, cannot perform reflections on version " + javaVersion, e);
++            }
++        }
++    }
++
++    public static void jdklatest_modifyFinal(Class<?> clazz, String fieldName, Object instance, Object value) throws NoSuchFieldException, IllegalAccessException {
++        final Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe");
++        unsafeField.setAccessible(true);
++        final Unsafe unsafe = (Unsafe) unsafeField.get(null);
++
++        final Field field = clazz.getDeclaredField(fieldName);
++        unsafe.putObject(instance, unsafe.objectFieldOffset(field), value);
++    }
++
++    public static void jdk8_modifyFinal(Class<?> clazz, String fieldName, Object instance, Object value) throws NoSuchFieldException, IllegalAccessException {
++        Field field = clazz.getDeclaredField(fieldName);
++        field.setAccessible(true);
++
++        Field modifiers = Field.class.getDeclaredField("modifiers");
++        modifiers.setAccessible(true);
++        modifiers.setInt(field, field.getModifiers() & ~Modifier.FINAL);
++
++        field.set(instance, value);
++    }
++}
+-- 
+2.39.5 (Apple Git-154)
+

patches/server/0223-Fix-JDK12-final-field-modification-issues.patch

@@ -0,0 +1,60 @@
+From bca366f2a4ed49ada403e19373383e7f39c93e5d Mon Sep 17 00:00:00 2001
+From: Jason Ho <[email protected]>
+Date: Sat, 24 Aug 2024 23:01:02 -0700
+Subject: [PATCH] Fix JDK12+ final field modification issues
+
+
+diff --git a/src/main/java/org/github/paperspigot/PaperSpigotConfig.java b/src/main/java/org/github/paperspigot/PaperSpigotConfig.java
+index 8cdcaf3a..6bdf4134 100644
+--- a/src/main/java/org/github/paperspigot/PaperSpigotConfig.java
++++ b/src/main/java/org/github/paperspigot/PaperSpigotConfig.java
+@@ -5,6 +5,7 @@ import java.lang.reflect.Modifier;
+ import java.util.*;
+ import java.util.logging.Level;
+
++import app.ashcon.sportpaper.api.reflection.ReflectionUtils;
+ import app.ashcon.sportpaper.server.KnockbackModificationCommand;
+ import net.minecraft.server.Items;
+ import org.apache.commons.lang.StringUtils;
+@@ -162,33 +163,22 @@ public class PaperSpigotConfig
+         stackableWaterBuckets = getBoolean( "stackable-buckets.water", false );
+         stackableMilkBuckets = getBoolean( "stackable-buckets.milk", false );
+
+-        Field maxStack;
+-
+-        try {
+-            maxStack = Material.class.getDeclaredField("maxStack");
+-            maxStack.setAccessible(true);
+-
+-            Field modifiers = Field.class.getDeclaredField("modifiers");
+-            modifiers.setAccessible(true);
+-            modifiers.setInt(maxStack, maxStack.getModifiers() & ~Modifier.FINAL);
+-        } catch (Exception e) {
+-            e.printStackTrace();
+-            return;
+-        }
++        Class<Material> materialClass = Material.class;
++        String maxStackFieldName = "maxStack";
+
+         try {
+             if (stackableLavaBuckets) {
+-                maxStack.set(Material.LAVA_BUCKET, Material.BUCKET.getMaxStackSize());
++                ReflectionUtils.modifyFinal(materialClass, maxStackFieldName, Material.LAVA_BUCKET, Material.BUCKET.getMaxStackSize());
+                 Items.LAVA_BUCKET.c(Material.BUCKET.getMaxStackSize());
+             }
+
+             if (stackableWaterBuckets) {
+-                maxStack.set(Material.WATER_BUCKET, Material.BUCKET.getMaxStackSize());
++                ReflectionUtils.modifyFinal(materialClass, maxStackFieldName, Material.WATER_BUCKET, Material.BUCKET.getMaxStackSize());
+                 Items.WATER_BUCKET.c(Material.BUCKET.getMaxStackSize());
+             }
+
+             if (stackableMilkBuckets) {
+-                maxStack.set(Material.MILK_BUCKET, Material.BUCKET.getMaxStackSize());
++                ReflectionUtils.modifyFinal(materialClass, maxStackFieldName, Material.MILK_BUCKET, Material.BUCKET.getMaxStackSize());
+                 Items.MILK_BUCKET.c(Material.BUCKET.getMaxStackSize());
+             }
+         } catch (Exception e) {
+-- 
+2.39.5 (Apple Git-154)
+