Mod runs in Eclipse, but crashes when loading built jar mod. (1.16.5)

[RedBobKid]

My mod works and is able to fully load when in Eclipse, the runClient task works without issue, but when I build the mod and run the jar file on the same Forge version as my MDK (36.2.34) it crashes with the error "java.lang.ClassFormatError: Duplicate method name "func_200929_c" with signature "()F" in class file sword/red/main/init/ModItemTier$ModItemTiers"

 

This is the crash report and file stated from the mod.

package sword.red.main.init;

import java.util.function.Supplier;
import net.minecraft.item.IItemTier;
import net.minecraft.item.crafting.Ingredient;
import net.minecraft.util.IItemProvider;
import net.minecraft.util.LazyValue;

public class ModItemTier {

    public static enum ModItemTiers implements IItemTier
    {
        PHOCKTONIUM(4, 4500, 12.0f, 8.0f, 100, () -> Ingredient.of((IItemProvider[])new IItemProvider[]{ModItemRegistry.PHOCKTONIUM_INGOT.get()}));
        
        private final int harvestLevel;
        private final int maxUses;
        private final int enchantability;
        private final float attackDamage;
        private final float efficiency;
        private final LazyValue<Ingredient> repairMaterial;

        private ModItemTiers(int harvestLevel, int maxUses, float efficency, float attackDamage, int enchantability, Supplier<Ingredient> repairMaterial) {
            this.harvestLevel = harvestLevel;
            this.maxUses = maxUses;
            this.efficiency = efficency;
            this.attackDamage = attackDamage;
            this.enchantability = enchantability;
            this.repairMaterial = new LazyValue<Ingredient>(repairMaterial);
        }

        public float func_200929_c() {
            return this.attackDamage;
        }

        public float func_200928_b() {
            return this.efficiency;
        }

        public int func_200927_e() {
            return this.enchantability;
        }

        public int func_200925_d() {
            return this.harvestLevel;
        }

        public int func_200926_a() {
            return this.maxUses;
        }

        public Ingredient func_200924_f() {
            return (Ingredient)this.repairMaterial.get();
        }

		@Override
		public float getAttackDamageBonus() {
			// TODO Auto-generated method stub
			return 0;
		}

		@Override
		public int getEnchantmentValue() {
			// TODO Auto-generated method stub
			return 0;
		}

		@Override
		public int getLevel() {
			// TODO Auto-generated method stub
			return 0;
		}

		@Override
		public Ingredient getRepairIngredient() {
			// TODO Auto-generated method stub
			return null;
		}

		@Override
		public float getSpeed() {
			// TODO Auto-generated method stub
			return 0;
		}

		@Override
		public int getUses() {
			// TODO Auto-generated method stub
			return 0;
		}
    }

}

---- Minecraft Crash Report ----
// You should try our sister game, Minceraft!

Time: 4/26/22 6:43 PM
Description: Mod loading error has occurred

java.lang.Exception: Mod Loading has failed
	at net.minecraftforge.fml.CrashReportExtender.dumpModLoadingCrashReport(CrashReportExtender.java:85) ~[forge:?] {re:classloading}
	at net.minecraftforge.fml.client.ClientModLoader.completeModLoading(ClientModLoader.java:188) ~[forge:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.lambda$null$1(Minecraft.java:508) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.util.Util.func_215077_a(Util.java:320) ~[?:?] {re:classloading}
	at net.minecraft.client.Minecraft.lambda$new$2(Minecraft.java:504) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.ResourceLoadProgressGui.func_230430_a_(ResourceLoadProgressGui.java:113) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.renderer.GameRenderer.func_195458_a(GameRenderer.java:481) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.func_195542_b(Minecraft.java:977) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:607) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:184) ~[client-1.16.5.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_281] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_281] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_281] {}
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_281] {}
	at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51) ~[forge-1.16.5-36.2.34.jar:36.2] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:82) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:66) [modlauncher-8.1.3.jar:?] {}


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Render thread
Stacktrace:
	at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_281] {}
-- MOD phocktoniumtoolsmod --
Details:
	Mod File: output.jar
	Failure message: Phocktonium Tools (phocktoniumtoolsmod) encountered an error during the load_registries event phase
		java.lang.ClassFormatError: Duplicate method name "func_200929_c" with signature "()F" in class file sword/red/main/init/ModItemTier$ModItemTiers
	Mod Version: 2.2
	Mod Issue URL: http://my.issue.tracker/
	Exception message: java.lang.ClassFormatError: Duplicate method name "func_200929_c" with signature "()F" in class file sword/red/main/init/ModItemTier$ModItemTiers
Stacktrace:
	at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.8.0_281] {}
	at java.lang.ClassLoader.defineClass(ClassLoader.java:756) ~[?:1.8.0_281] {}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:138) ~[modlauncher-8.1.3.jar:?] {re:classloading}
	at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:98) ~[modlauncher-8.1.3.jar:?] {re:classloading}
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[?:1.8.0_281] {}
	at sword.red.main.ModEventSubscriber.onRegisterItems(ModEventSubscriber.java:34) ~[phocktoniumtoolsmod:2.2] {re:classloading}
	at net.minecraftforge.eventbus.ASMEventHandler_7_ModEventSubscriber_onRegisterItems_Register.invoke(.dynamic) ~[?:?] {}
	at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.fml.javafmlmod.FMLModContainer.acceptEvent(FMLModContainer.java:120) ~[forge:36.2] {re:classloading}
	at net.minecraftforge.fml.ModContainer.lambda$buildTransitionHandler$4(ModContainer.java:121) ~[forge:?] {re:classloading}
	at java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1640) ~[?:1.8.0_281] {}
	at net.minecraftforge.fml.ModWorkManager$SyncExecutor.driveOne(ModWorkManager.java:56) ~[forge:?] {re:classloading}
	at net.minecraftforge.fml.ModWorkManager$DrivenExecutor.drive(ModWorkManager.java:40) ~[forge:?] {re:classloading}
	at net.minecraftforge.fml.ModLoader.waitForTransition(ModLoader.java:249) ~[forge:?] {re:classloading}
	at net.minecraftforge.fml.ModLoader.dispatchAndHandleError(ModLoader.java:236) ~[forge:?] {re:classloading}
	at net.minecraftforge.fml.ModLoader.gatherAndInitializeMods(ModLoader.java:202) ~[forge:?] {re:classloading}
	at net.minecraftforge.fml.client.ClientModLoader.lambda$begin$1(ClientModLoader.java:103) ~[forge:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraftforge.fml.client.ClientModLoader.lambda$createRunnableWithCatch$4(ClientModLoader.java:123) ~[forge:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraftforge.fml.client.ClientModLoader.begin(ClientModLoader.java:103) ~[forge:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.<init>(Minecraft.java:437) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:149) ~[client-1.16.5.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_281] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_281] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_281] {}
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_281] {}
	at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51) ~[forge-1.16.5-36.2.34.jar:36.2] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:82) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:66) [modlauncher-8.1.3.jar:?] {}


-- System Details --
Details:
	Minecraft Version: 1.16.5
	Minecraft Version ID: 1.16.5
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_281, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 1283733216 bytes (1224 MB) / 2235039744 bytes (2131 MB) up to 5249695744 bytes (5006 MB)
	CPUs: 4
	JVM Flags: 7 total; -XX:-OmitStackTraceInFastThrow -Xms512M -Xmx5632M -XX:MetaspaceSize=352M -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -XX:+IgnoreUnrecognizedVMOptions
	ModLauncher: 8.1.3+8.1.3+main-8.1.x.c94d18ec
	ModLauncher launch target: fmlclient
	ModLauncher naming: srg
	ModLauncher services: 
		/mixin-0.8.4.jar mixin PLUGINSERVICE 
		/eventbus-4.0.0.jar eventbus PLUGINSERVICE 
		/forge-1.16.5-36.2.34.jar object_holder_definalize PLUGINSERVICE 
		/forge-1.16.5-36.2.34.jar runtime_enum_extender PLUGINSERVICE 
		/accesstransformers-3.0.1.jar accesstransformer PLUGINSERVICE 
		/forge-1.16.5-36.2.34.jar capability_inject_definalize PLUGINSERVICE 
		/forge-1.16.5-36.2.34.jar runtimedistcleaner PLUGINSERVICE 
		/mixin-0.8.4.jar mixin TRANSFORMATIONSERVICE 
		/forge-1.16.5-36.2.34.jar fml TRANSFORMATIONSERVICE 
	FML: 36.2
	Forge: net.minecraftforge:36.2.34
	FML Language Providers: 
		javafml@36.2
		minecraft@1
	Mod List: 
		forge-1.16.5-36.2.34-client.jar                   |Minecraft                     |minecraft                     |1.16.5              |COMMON_SET|Manifest: NOSIGNATURE
		output.jar                                        |Phocktonium Tools             |phocktoniumtoolsmod           |2.2                 |VALIDATE  |Manifest: NOSIGNATURE
		forge-1.16.5-36.2.34-universal.jar                |Forge                         |forge                         |36.2.34             |COMMON_SET|Manifest: 22:af:21:d8:19:82:7f:93:94:fe:2b:ac:b7:e4:41:57:68:39:87:b1:a7:5c:c6:44:f9:25:74:21:14:f5:0d:90
	Crash Report UUID: 6d8b3ea4-ac40-4eb7-9735-02f80058dc20