[SOLVED] Minecraft Crashes While Loading The World

This is the latest crash report saved in 'crash-reports' file.

---- Minecraft Crash Report ----
// Why did you do that?

Time: 28.05.2020 09:46
Description: Ticking player

java.lang.ArrayIndexOutOfBoundsException: 103
    at java.util.Arrays$ArrayList.get(Arrays.java:3841) ~[?:1.8.0_252] {}
    at net.minecraft.util.NonNullList.get(NonNullList.java:45) ~[forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-recomp.jar:?] {re:classloading}
    at noyb.mod.testmod.procedures.FullArmorProcedure.executeProcedure(FullArmorProcedure.java:31) ~[main/:?] {re:classloading}
    at noyb.mod.testmod.procedures.FullArmorProcedure.onPlayerTick(FullArmorProcedure.java:59) ~[main/:?] {re:classloading}
    at net.minecraftforge.eventbus.ASMEventHandler_4_FullArmorProcedure_onPlayerTick_PlayerTickEvent.invoke(.dynamic) ~[?:?] {}
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-2.2.0-service.jar:?] {}
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-2.2.0-service.jar:?] {}
    at net.minecraftforge.fml.hooks.BasicEventHooks.onPlayerPostTick(BasicEventHooks.java:89) ~[?:?] {re:classloading}
    at net.minecraft.entity.player.PlayerEntity.tick(PlayerEntity.java:284) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.entity.player.ServerPlayerEntity.playerTick(ServerPlayerEntity.java:379) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.network.play.ServerPlayNetHandler.tick(ServerPlayNetHandler.java:188) ~[?:?] {re:classloading}
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:250) ~[?:?] {re:classloading}
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:152) ~[?:?] {re:classloading}
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:903) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:821) ~[?:?] {re:classloading,pl:accesstransformer:B}
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:120) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:662) [?:?] {re:classloading,pl:accesstransformer:B}
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_252] {}

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

-- Head --
Thread: Server thread
Stacktrace:
    at java.util.Arrays$ArrayList.get(Arrays.java:3841)
    at net.minecraft.util.NonNullList.get(NonNullList.java:45)
    at noyb.mod.testmod.procedures.FullArmorProcedure.executeProcedure(FullArmorProcedure.java:31)
    at noyb.mod.testmod.procedures.FullArmorProcedure.onPlayerTick(FullArmorProcedure.java:59)
    at net.minecraftforge.eventbus.ASMEventHandler_4_FullArmorProcedure_onPlayerTick_PlayerTickEvent.invoke(.dynamic)
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80)
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258)
    at net.minecraftforge.fml.hooks.BasicEventHooks.onPlayerPostTick(BasicEventHooks.java:89)
    at net.minecraft.entity.player.PlayerEntity.tick(PlayerEntity.java:284)

-- Player being ticked --
Details:
    Entity Type: minecraft:player (net.minecraft.entity.player.ServerPlayerEntity)
    Entity ID: 123
    Entity Name: Dev
    Entity's Exact location: 86.50, 64.00, 21.50
    Entity's Block location: World: (86,64,21), Chunk: (at 6,4,5 in 5,1; contains blocks 80,0,16 to 95,255,31), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
    Entity's Momentum: 0.00, -0.08, 0.00
    Entity's Passengers: []
    Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
    at net.minecraft.entity.player.ServerPlayerEntity.playerTick(ServerPlayerEntity.java:379)
    at net.minecraft.network.play.ServerPlayNetHandler.tick(ServerPlayNetHandler.java:188)
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:250)

-- Ticking connection --
Details:
    Connection: net.minecraft.network.NetworkManager@52a767a7
Stacktrace:
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:152)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:903)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:821)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:120)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:662)
    at java.lang.Thread.run(Thread.java:748)

-- System Details --
Details:
    Minecraft Version: 1.15.2
    Minecraft Version ID: 1.15.2
    Operating System: Windows 10 (amd64) version 10.0
    Java Version: 1.8.0_252, BellSoft
    Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), BellSoft
    Memory: 345703736 bytes (329 MB) / 1119354880 bytes (1067 MB) up to 1894252544 bytes (1806 MB)
    CPUs: 4
    JVM Flags: 1 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump
    ModLauncher: 5.1.0+69+master.79f13f7
    ModLauncher launch target: fmluserdevclient
    ModLauncher naming: mcp
    ModLauncher services: 
        /eventbus-2.2.0-service.jar eventbus PLUGINSERVICE 
        /forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-launcher.jar object_holder_definalize PLUGINSERVICE 
        /forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-launcher.jar runtime_enum_extender PLUGINSERVICE 
        /accesstransformers-2.1.1-shadowed.jar accesstransformer PLUGINSERVICE 
        /forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-launcher.jar capability_inject_definalize PLUGINSERVICE 
        /forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-launcher.jar runtimedistcleaner PLUGINSERVICE 
        /forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-launcher.jar fml TRANSFORMATIONSERVICE 
    FML: 31.2
    Forge: net.minecraftforge:31.2.0
    FML Language Providers: 
        javafml@31.2
        minecraft@1
    Mod List: 
        client-extra.jar Minecraft {minecraft@1.15.2 DONE}
        forge-1.15.2-31.2.0_mapped_snapshot_20200514-1.15.1-recomp.jar Forge {forge@31.2.0 DONE}
        main Test Mod {testmod@Test Mod DONE}
    Player Count: 1 / 8; [ServerPlayerEntity['Dev'/123, l='Test World', x=86.50, y=64.00, z=21.50]]
    Data Packs: vanilla, mod:forge (incompatible), mod:testmod
    Type: Integrated Server (map_client.txt)
    Is Modded: Definitely; Client brand changed to 'forge'

Here it is: https://imgur.com/BYoWE94

I think I specified the wrong slots.

Yeah, that was the problem. Thanks for your help, but I would like to ask one more thing. Sometimes Minecraft crashes saying 'Insufficient memory for Java Runtime Environment to contunie', how can I prevent this from happening because there is no way my RAM is insufficient. It doesn't even use half of it.

I googled the slot IDs of player inventory, actually it looked strange but I didn't questioned the Google