So I have my workspace and my Forge project set up (as per tutorial, now), and have one functional mod written sitting there as a package. The Minecraft client used for testing runs properly and the command the mod adds works as expected.

 

I create another package, set it up with a basic modfile, and attempt to run the client. This time it fails to work, and gives me errors:

 

[18:23:46] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[18:23:46] [main/INFO] [LaunchWrapper]: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[18:23:46] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker
[18:23:46] [main/INFO] [FML]: Forge Mod Loader version 7.2.211.1121 for Minecraft 1.7.2 loading
[18:23:46] [main/INFO] [FML]: Java is Java HotSpot(TM) 64-Bit Server VM, version 1.8.0_05, running on Windows 7:amd64:6.1, installed at C:\Program Files\Java\jre8
[18:23:46] [main/INFO] [FML]: Managed to load a deobfuscated Minecraft name- we are in a deobfuscated environment. Skipping runtime deobfuscation
[18:23:46] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker
[18:23:46] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker
[18:23:46] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker
[18:23:46] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker
[18:23:46] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.relauncher.CoreModManager$FMLPluginWrapper
[18:23:46] [main/ERROR] [FML]: The binary patch set is missing. Either you are in a development environment, or things are not going to work!
[18:23:47] [main/ERROR] [FML]: The minecraft jar file:/C:/Users/BECKYPC/.gradle/caches/minecraft/net/minecraftforge/forge/1.7.2-10.12.2.1121/forgeSrc-1.7.2-10.12.2.1121.jar!/net/minecraft/client/ClientBrandRetriever.class appears to be corrupt! There has been CRITICAL TAMPERING WITH MINECRAFT, it is highly unlikely minecraft will work! STOP NOW, get a clean copy and try again!
[18:23:47] [main/ERROR] [FML]: FML has been ordered to ignore the invalid or missing minecraft certificate. This is very likely to cause a problem!
[18:23:47] [main/ERROR] [FML]: Technical information: ClientBrandRetriever was at jar:file:/C:/Users/BECKYPC/.gradle/caches/minecraft/net/minecraftforge/forge/1.7.2-10.12.2.1121/forgeSrc-1.7.2-10.12.2.1121.jar!/net/minecraft/client/ClientBrandRetriever.class, there were 0 certificates for it
[18:23:47] [main/ERROR] [FML]: FML appears to be missing any signature data. This is not a good thing
[18:23:47] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.relauncher.CoreModManager$FMLPluginWrapper
[18:23:47] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLDeobfTweaker
[18:23:47] [main/INFO] [LaunchWrapper]: Launching wrapped minecraft {net.minecraft.client.main.Main}
[18:23:47] [main/INFO]: Setting user: Player897
[18:23:48] [Client thread/INFO]: LWJGL Version: 2.9.0
[18:23:49] [Client thread/INFO] [MinecraftForge]: Attempting early MinecraftForge initialization
[18:23:49] [Client thread/INFO] [FML]: MinecraftForge v10.12.2.1121 Initialized
[18:23:49] [Client thread/INFO] [FML]: Replaced 182 ore recipies
[18:23:49] [Client thread/INFO] [MinecraftForge]: Completed early MinecraftForge initialization
[18:23:49] [Client thread/INFO] [FML]: Searching G:\Projects\Nations at War\Coding\Forge\Forge\eclipse\mods for mods
[18:23:50] [Client thread/ERROR] [FML]: FML has detected a mod that is using a package name based on 'net.minecraft.src' : net.minecraft.src.FMLRenderAccessLibrary. This is generally a severe programming error.  There should be no mod code in the minecraft namespace. MOVE YOUR MOD! If you're in eclipse, select your source code and 'refactor' it into a new package. Go on. DO IT NOW!
[18:23:51] [Client thread/INFO] [FML]: Forge Mod Loader has identified 5 mods to load
Jun 22, 2014 6:23:51 PM com.google.common.eventbus.EventBus dispatch
SEVERE: Could not dispatch event: cpw.mods.fml.common.event.FMLConstructionEvent@4a68cbc5 to handler [wrapper public void cpw.mods.fml.common.FMLModContainer.constructMod(cpw.mods.fml.common.event.FMLConstructionEvent)]
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:491)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:204)
at net.minecraft.client.Minecraft.startGame(Minecraft.java:522)
at net.minecraft.client.Minecraft.run(Minecraft.java:892)
at net.minecraft.client.main.Main.main(Main.java:112)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.IllegalArgumentException: Can not set static com.feldherren.smokebomb.SmokebombMain field com.feldherren.smokebomb.SmokebombMain.instance to com.feldherren.moonphase.MoonphaseMain
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeStaticObjectFieldAccessorImpl.set(Unknown Source)
at java.lang.reflect.Field.set(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.parseSimpleFieldAnnotation(FMLModContainer.java:407)
at cpw.mods.fml.common.FMLModContainer.processFieldAnnotations(FMLModContainer.java:338)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:493)
... 32 more

Jun 22, 2014 6:23:51 PM com.google.common.eventbus.EventBus dispatch
SEVERE: Could not dispatch event: cpw.mods.fml.common.event.FMLConstructionEvent@4a68cbc5 to handler [wrapper public void cpw.mods.fml.common.FMLModContainer.constructMod(cpw.mods.fml.common.event.FMLConstructionEvent)]
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:491)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:204)
at net.minecraft.client.Minecraft.startGame(Minecraft.java:522)
at net.minecraft.client.Minecraft.run(Minecraft.java:892)
at net.minecraft.client.main.Main.main(Main.java:112)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.IllegalArgumentException: Can not set static com.feldherren.moonphase.MoonphaseMain field com.feldherren.moonphase.MoonphaseMain.instance to com.feldherren.smokebomb.SmokebombMain
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeStaticObjectFieldAccessorImpl.set(Unknown Source)
at java.lang.reflect.Field.set(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.parseSimpleFieldAnnotation(FMLModContainer.java:407)
at cpw.mods.fml.common.FMLModContainer.processFieldAnnotations(FMLModContainer.java:338)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:493)
... 32 more

[18:23:51] [Client thread/ERROR] [FML]: Fatal errors were detected during the transition from CONSTRUCTING to PREINITIALIZATION. Loading cannot continue
[18:23:51] [Client thread/ERROR] [FML]: 
mcp{9.03} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
FML{7.2.211.1121} [Forge Mod Loader] (forgeSrc-1.7.2-10.12.2.1121.jar) Unloaded->Constructed
Forge{10.12.2.1121} [Minecraft Forge] (forgeSrc-1.7.2-10.12.2.1121.jar) Unloaded->Constructed
moonphase{1.0} [Moon Phase Command] (bin) Unloaded->Errored
smokebomb{1.0.0} [smokebombs] (bin) Unloaded->Errored
[18:23:51] [Client thread/ERROR] [FML]: The following problems were captured during this phase
[18:23:51] [Client thread/ERROR] [FML]: Caught exception from moonphase
java.lang.IllegalArgumentException: Can not set static com.feldherren.smokebomb.SmokebombMain field com.feldherren.smokebomb.SmokebombMain.instance to com.feldherren.moonphase.MoonphaseMain
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.UnsafeStaticObjectFieldAccessorImpl.set(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Field.set(Unknown Source) ~[?:1.8.0_05]
at cpw.mods.fml.common.FMLModContainer.parseSimpleFieldAnnotation(FMLModContainer.java:407) ~[FMLModContainer.class:?]
at cpw.mods.fml.common.FMLModContainer.processFieldAnnotations(FMLModContainer.java:338) ~[FMLModContainer.class:?]
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:493) ~[FMLModContainer.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_05]
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74) ~[guava-15.0.jar:?]
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:267) ~[guava-15.0.jar:?]
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208) ~[LoadController.class:?]
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187) ~[LoadController.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_05]
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74) ~[guava-15.0.jar:?]
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:267) ~[guava-15.0.jar:?]
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118) [LoadController.class:?]
at cpw.mods.fml.common.Loader.loadMods(Loader.java:491) [Loader.class:?]
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:204) [FMLClientHandler.class:?]
at net.minecraft.client.Minecraft.startGame(Minecraft.java:522) [Minecraft.class:?]
at net.minecraft.client.Minecraft.run(Minecraft.java:892) [Minecraft.class:?]
at net.minecraft.client.main.Main.main(Main.java:112) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_05]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134) [launchwrapper-1.9.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]
[18:23:51] [Client thread/ERROR] [FML]: Caught exception from smokebomb
java.lang.IllegalArgumentException: Can not set static com.feldherren.moonphase.MoonphaseMain field com.feldherren.moonphase.MoonphaseMain.instance to com.feldherren.smokebomb.SmokebombMain
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.UnsafeStaticObjectFieldAccessorImpl.set(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Field.set(Unknown Source) ~[?:1.8.0_05]
at cpw.mods.fml.common.FMLModContainer.parseSimpleFieldAnnotation(FMLModContainer.java:407) ~[FMLModContainer.class:?]
at cpw.mods.fml.common.FMLModContainer.processFieldAnnotations(FMLModContainer.java:338) ~[FMLModContainer.class:?]
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:493) ~[FMLModContainer.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_05]
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74) ~[guava-15.0.jar:?]
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:267) ~[guava-15.0.jar:?]
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208) ~[LoadController.class:?]
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187) ~[LoadController.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_05]
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74) ~[guava-15.0.jar:?]
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296) ~[guava-15.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:267) ~[guava-15.0.jar:?]
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118) [LoadController.class:?]
at cpw.mods.fml.common.Loader.loadMods(Loader.java:491) [Loader.class:?]
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:204) [FMLClientHandler.class:?]
at net.minecraft.client.Minecraft.startGame(Minecraft.java:522) [Minecraft.class:?]
at net.minecraft.client.Minecraft.run(Minecraft.java:892) [Minecraft.class:?]
at net.minecraft.client.main.Main.main(Main.java:112) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_05]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_05]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_05]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134) [launchwrapper-1.9.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]
[18:23:51] [Client thread/INFO]: Reloading ResourceManager: Default, FMLFileResourcePack:Forge Mod Loader, FMLFileResourcePack:Minecraft Forge, FMLFileResourcePack:Moon Phase Command, FMLFileResourcePack:Smokebombs
---- Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!

Time: 22/06/14 18:23
Description: Initializing game

java.lang.IllegalArgumentException: Can not set static com.feldherren.smokebomb.SmokebombMain field com.feldherren.smokebomb.SmokebombMain.instance to com.feldherren.moonphase.MoonphaseMain
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeStaticObjectFieldAccessorImpl.set(Unknown Source)
at java.lang.reflect.Field.set(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.parseSimpleFieldAnnotation(FMLModContainer.java:407)
at cpw.mods.fml.common.FMLModContainer.processFieldAnnotations(FMLModContainer.java:338)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:493)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:491)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:204)
at net.minecraft.client.Minecraft.startGame(Minecraft.java:522)
at net.minecraft.client.Minecraft.run(Minecraft.java:892)
at net.minecraft.client.main.Main.main(Main.java:112)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
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 sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(Unknown Source)
at sun.reflect.UnsafeStaticObjectFieldAccessorImpl.set(Unknown Source)
at java.lang.reflect.Field.set(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.parseSimpleFieldAnnotation(FMLModContainer.java:407)
at cpw.mods.fml.common.FMLModContainer.processFieldAnnotations(FMLModContainer.java:338)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:493)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:208)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:187)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:491)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:204)
at net.minecraft.client.Minecraft.startGame(Minecraft.java:522)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.Minecraft.run(Minecraft.java:892)
at net.minecraft.client.main.Main.main(Main.java:112)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

-- System Details --
Details:
Minecraft Version: 1.7.2
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.8.0_05, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 867881064 bytes (827 MB) / 1037959168 bytes (989 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 3 total; -Xincgc -Xmx1024M -Xms1024M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v9.03 FML v7.2.211.1121 Minecraft Forge 10.12.2.1121 5 mods loaded, 5 mods active
mcp{9.03} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
FML{7.2.211.1121} [Forge Mod Loader] (forgeSrc-1.7.2-10.12.2.1121.jar) Unloaded->Constructed
Forge{10.12.2.1121} [Minecraft Forge] (forgeSrc-1.7.2-10.12.2.1121.jar) Unloaded->Constructed
moonphase{1.0} [Moon Phase Command] (bin) Unloaded->Errored
smokebomb{1.0.0} [smokebombs] (bin) Unloaded->Errored
Launched Version: 1.6
LWJGL: 2.9.0
OpenGL: GeForce GTX 680/PCIe/SSE2 GL version 4.4.0, NVIDIA Corporation
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: []
Current Language: English (US)
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null
Anisotropic Filtering: Off (1)
#@!@# Game crashed! Crash report saved to: #@!@# G:\Projects\Nations at War\Coding\Forge\Forge\eclipse\.\crash-reports\crash-2014-06-22_18.23.51-client.txt
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release

 

Delete the new package, and it starts to work again.

 

I notice that it's attempting to set the instance of each package to the main class of the other package.

Is this a likely cause of the issue? Or would you need the code from the two packages to work out what's going on? I can post that, but don't want to if it's something basic.

 

So am I doing something stupid, or can you just not (without doing stuff to prevent this issue) work on more than one package at once?

And in either case, can this problem be prevented?

Okay. To make sure I'm getting this correct... well, I tested and it works, but this is more to provide the answer for anyone who gets the same issue and to make sure I'm not doing something that will cause issues for me further down the line, instead of just doing:

 

@instance

 

...prior to setting up the instance, I want to do:

 

@instance(value = [MainClassHere].MODID)

 

Right?

Okay. Thank you very much for your help. That solved it.