diff --git a/fml/common/cpw/mods/fml/relauncher/FMLRelauncher.java b/fml/common/cpw/mods/fml/relauncher/FMLRelauncher.java
index 3fe3fe7b5..599706a91 100644
--- a/fml/common/cpw/mods/fml/relauncher/FMLRelauncher.java
+++ b/fml/common/cpw/mods/fml/relauncher/FMLRelauncher.java
@@ -132,8 +132,8 @@ public class FMLRelauncher
     private Class<? super Object> setupNewClientHome(File minecraftHome)
     {
         Class<? super Object> client = ReflectionHelper.getClass(classLoader, "net.minecraft.client.Minecraft");
-        ReflectionHelper.setPrivateValue(client, null, minecraftHome, 
-                "field_" + "71463_am" /*Separate that so that MCP's updatenames does not replace it*/, 
+        ReflectionHelper.setPrivateValue(client, null, minecraftHome,
+                "field_" + "71463_am" /*Separate that so that MCP's updatenames does not replace it*/,
                 "an", "minecraftDir");
         return client;
     }
@@ -163,6 +163,9 @@ public class FMLRelauncher
         FMLRelaunchLog.minecraftHome = minecraftHome;
         FMLRelaunchLog.info("Forge Mod Loader version %s.%s.%s.%s for Minecraft %s loading", FMLInjectionData.major, FMLInjectionData.minor,
                 FMLInjectionData.rev, FMLInjectionData.build, FMLInjectionData.mccversion, FMLInjectionData.mcpversion);
+        FMLRelaunchLog.info("Java is %s, version %s, running on %s:%s:%s, installed at %s", System.getProperty("java.vm.name"), System.getProperty("java.version"), System.getProperty("os.name"), System.getProperty("os.arch"), System.getProperty("os.version"), System.getProperty("java.home"));
+        FMLRelaunchLog.fine("Java classpath at launch is %s", System.getProperty("java.class.path"));
+        FMLRelaunchLog.fine("Java library path at launch is %s", System.getProperty("java.library.path"));
 
         try
         {
diff --git a/fml/common/cpw/mods/fml/relauncher/IFMLLoadingPlugin.java b/fml/common/cpw/mods/fml/relauncher/IFMLLoadingPlugin.java
index a389da18b..3561ebf51 100644
--- a/fml/common/cpw/mods/fml/relauncher/IFMLLoadingPlugin.java
+++ b/fml/common/cpw/mods/fml/relauncher/IFMLLoadingPlugin.java
@@ -5,7 +5,7 @@
  * are made available under the terms of the GNU Lesser Public License v2.1
  * which accompanies this distribution, and is available at
  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
- * 
+ *
  * Contributors:
  *     cpw - implementation
  */
@@ -87,4 +87,18 @@ public interface IFMLLoadingPlugin
     {
         public String[] value() default "";
     }
+
+    /**
+     * Use this to target a specific minecraft version for your coremod. It will refuse to load with an error if
+     * minecraft is not this exact version.
+     *
+     * @author cpw
+     *
+     */
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.TYPE)
+    public @interface MCVersion
+    {
+        public String value() default "";
+    }
 }
diff --git a/fml/common/cpw/mods/fml/relauncher/RelaunchLibraryManager.java b/fml/common/cpw/mods/fml/relauncher/RelaunchLibraryManager.java
index 47abc7b13..58e8017a1 100644
--- a/fml/common/cpw/mods/fml/relauncher/RelaunchLibraryManager.java
+++ b/fml/common/cpw/mods/fml/relauncher/RelaunchLibraryManager.java
@@ -38,6 +38,7 @@ import java.util.jar.JarFile;
 import java.util.logging.Level;
 
 import cpw.mods.fml.common.CertificateHelper;
+import cpw.mods.fml.relauncher.IFMLLoadingPlugin.MCVersion;
 import cpw.mods.fml.relauncher.IFMLLoadingPlugin.TransformerExclusions;
 
 public class RelaunchLibraryManager
@@ -406,6 +407,17 @@ public class RelaunchLibraryManager
                 downloadMonitor.updateProgressString("Loading coremod %s", coreMod.getName());
                 classLoader.addTransformerExclusion(fmlCorePlugin);
                 Class<?> coreModClass = Class.forName(fmlCorePlugin, true, classLoader);
+                MCVersion requiredMCVersion = coreModClass.getAnnotation(IFMLLoadingPlugin.MCVersion.class);
+                String version = requiredMCVersion.value();
+                if (!"".equals(version) && !FMLInjectionData.mccversion.equals(version))
+                {
+                    FMLRelaunchLog.log(Level.SEVERE, "The coremod %s is requesting minecraft version %s and minecraft is %s. It will be ignored.", fmlCorePlugin, version, FMLInjectionData.mccversion);
+                    continue;
+                }
+                else if (!"".equals(version))
+                {
+                    FMLRelaunchLog.log(Level.FINE, "The coremod %s requested minecraft version %s and minecraft is %s. It will be loaded.", fmlCorePlugin, version, FMLInjectionData.mccversion);
+                }
                 TransformerExclusions trExclusions = coreModClass.getAnnotation(IFMLLoadingPlugin.TransformerExclusions.class);
                 if (trExclusions!=null)
                 {