Does forge not allow two forges at once?

[Carpet6142]

I have forge 1.8.9 and force 1.14.4. When I remove 1.14.4, I can use 1.8.9. But when I keep it, 1.8.9 doesn't work, but 1.14.4 does work. So I was wondering if two forge mods can't exist in the same mod folder? It just says crash: 

 

 

 

 

---- Minecraft Crash Report ----

WARNING: coremods are present:
Contact their authors BEFORE contacting forge

// Don't do that.

Time: 11/8/19 4:00 PM
Description: Initializing game

java.lang.NullPointerException: Initializing game
    at net.minecraftforge.fml.common.Loader$ModIdComparator.compare(Loader.java:375)
    at net.minecraftforge.fml.common.Loader$ModIdComparator.compare(Loader.java:370)
    at java.util.TreeMap.getEntryUsingComparator(TreeMap.java:376)
    at java.util.TreeMap.getEntry(TreeMap.java:345)
    at java.util.TreeMap.get(TreeMap.java:278)
    at com.google.common.collect.AbstractMapBasedMultimap.put(AbstractMapBasedMultimap.java:192)
    at com.google.common.collect.AbstractSetMultimap.put(AbstractSetMultimap.java:121)
    at com.google.common.collect.TreeMultimap.put(TreeMultimap.java:78)
    at net.minecraftforge.fml.common.Loader.identifyDuplicates(Loader.java:386)
    at net.minecraftforge.fml.common.Loader.identifyMods(Loader.java:364)
    at net.minecraftforge.fml.common.Loader.loadMods(Loader.java:488)
    at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:208)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:417)
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:329)
    at net.minecraft.client.main.Main.main(SourceFile:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

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

-- Head --
Stacktrace:
    at net.minecraftforge.fml.common.Loader$ModIdComparator.compare(Loader.java:375)
    at net.minecraftforge.fml.common.Loader$ModIdComparator.compare(Loader.java:370)
    at java.util.TreeMap.getEntryUsingComparator(TreeMap.java:376)
    at java.util.TreeMap.getEntry(TreeMap.java:345)
    at java.util.TreeMap.get(TreeMap.java:278)
    at com.google.common.collect.AbstractMapBasedMultimap.put(AbstractMapBasedMultimap.java:192)
    at com.google.common.collect.AbstractSetMultimap.put(AbstractSetMultimap.java:121)
    at com.google.common.collect.TreeMultimap.put(TreeMultimap.java:78)
    at net.minecraftforge.fml.common.Loader.identifyDuplicates(Loader.java:386)
    at net.minecraftforge.fml.common.Loader.identifyMods(Loader.java:364)
    at net.minecraftforge.fml.common.Loader.loadMods(Loader.java:488)
    at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:208)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:417)

-- Initialization --
Details:
Stacktrace:
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:329)
    at net.minecraft.client.main.Main.main(SourceFile:124)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

-- System Details --
Details:
    Minecraft Version: 1.8.9
    Operating System: Windows 10 (amd64) version 10.0
    Java Version: 1.8.0_51, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 307351640 bytes (293 MB) / 536870912 bytes (512 MB) up to 2147483648 bytes (2048 MB)
    JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
    IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
    FML: MCP 9.19 Powered by Forge 11.15.1.1722 7 mods loaded, 0 mods active
    States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
        mcp{9.19} [Minecraft Coder Pack] (minecraft.jar) 
        FML{8.0.99.99} [Forge Mod Loader] (forge-1.8.9-11.15.1.1722.jar) 
        Forge{11.15.1.1722} [Minecraft Forge] (forge-1.8.9-11.15.1.1722.jar) 
        skyblockaddons{1.4.0} [SkyBlock Addons] (SkyblockAddons-1.4.0-for-MC-1.8.9 (1).jar) 
        null{1.0} [null] (FunItems-Mod-1.14.4.jar) 
        null{1.0} [null] (Mutant-Beasts-1.14.4.jar) 
        null{1.0} [null] (SuperTools-1.6b.jar) 
    Loaded coremods (and transformers): 
    GL info: ' Vendor: 'ATI Technologies Inc.' Version: '4.5.13399 Compatibility Profile Context 15.201.1151.1008' Renderer: 'AMD Radeon HD 7000 series'
    Launched Version: 1.8.9-forge1.8.9-11.15.1.1722
    LWJGL: 2.9.4
    OpenGL: AMD Radeon HD 7000 series GL version 4.5.13399 Compatibility Profile Context 15.201.1151.1008, ATI Technologies Inc.
    GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

    Using VBOs: No
    Is Modded: Definitely; Client brand changed to 'fml,forge'
    Type: Client (map_client.txt)
    Resource Packs: vanilla
    Current Language: English (US)
    Profiler Position: N/A (disabled)
    CPU: 8x Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz

Edited November 8, 2019 by Carpet6142

[DavidM]

You can have different versions of Forge installed at the same time.

They won’t interfere with each other.

 

Your crash is caused by trying to load 1.14.4 mods in 1.8.9. This won’t work.

Edited November 9, 2019 by DavidM

[DaemonUmbra]

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