NO longer generate the class dynamicly, just 2 different classes for 2 supported versions will be enough

src/com/cnaude/chairs/vehiclearrow/GenVehicleArrowClass.java

@@ -1,49 +0,0 @@
-package com.cnaude.chairs.vehiclearrow;
-
-import java.io.IOException;
-
-import org.bukkit.Bukkit;
-import org.bukkit.entity.Vehicle;
-
-import javassist.CannotCompileException;
-import javassist.ClassClassPath;
-import javassist.ClassPool;
-import javassist.CtClass;
-import javassist.CtNewConstructor;
-import javassist.CtNewMethod;
-import javassist.NotFoundException;
-
-public class GenVehicleArrowClass {
-
-	public Class<?> genAndLoadClass(String arrowclass, Class<?> entityarrow, Class<?> craftserver) throws IOException, ClassNotFoundException, NotFoundException, CannotCompileException 
-	{
-		ClassPool pool = ClassPool.getDefault();
-		pool.insertClassPath
-		(
-				new ClassClassPath(Bukkit.class)
-		);
-		CtClass vehiclearrow = pool.makeClass("com.cnaude.chairs.VehicleArrow");
-		vehiclearrow.setSuperclass(pool.getCtClass(arrowclass));
-		vehiclearrow.setInterfaces
-		(
-			new CtClass[]
-			{
-				pool.get(Vehicle.class.getName())
-			}
-		);
-		String counstructorsource = "public VehicleArrow("+craftserver.getName()+" server, "+entityarrow.getName()+" entity)\n{\nsuper(server, entity);\n}";
-		vehiclearrow.addConstructor
-		(
-				CtNewConstructor.make(counstructorsource, vehiclearrow)
-		);
-		String removemethodsource = "public void remove()\n{\nif (this.getPassenger() == null)\n{\nsuper.remove();\n}\n}";
-		vehiclearrow.addMethod
-		(
-			CtNewMethod.make(removemethodsource, vehiclearrow)
-		);
-		return vehiclearrow.toClass();
-	}
-
-
-	
-}

src/com/cnaude/chairs/vehiclearrow/GetVehicleArrowClass.java

@@ -0,0 +1,25 @@
+package com.cnaude.chairs.vehiclearrow;
+
+import org.bukkit.Bukkit;
+
+public class GetVehicleArrowClass {
+
+	private String pkgname = this.getClass().getPackage().getName();
+	private String vehiclearrowclassname = "VehicleArrow";
+	public Class<?> getVehicleArrowClass(String arrowclass, Class<?> entityarrow, Class<?> craftserver) throws Exception
+	{
+        String packageName = Bukkit.getServer().getClass().getPackage().getName();
+        String nmspackageversion = packageName.substring(packageName.lastIndexOf('.') + 1);
+        if (nmspackageversion.equals("v1_7_R1"))
+        {
+        	return Class.forName(pkgname+"."+"nms172"+"."+vehiclearrowclassname);
+        } else if (nmspackageversion.equals("v1_6_R3"))
+        {
+        	return Class.forName(pkgname+"."+"nms164"+"."+vehiclearrowclassname);
+        }
+        throw new Exception("ChiarsReloaded is not compatible with your server version");
+	}
+
+
+	
+}

src/com/cnaude/chairs/vehiclearrow/nms164/VehicleArrow.java

@@ -0,0 +1,5 @@
+package com.cnaude.chairs.vehiclearrow.nms164;
+
+public class VehicleArrow {
+
+}

src/com/cnaude/chairs/vehiclearrow/nms172/VehicleArrow.java

@@ -0,0 +1,25 @@
+package com.cnaude.chairs.vehiclearrow.nms172;
+
+import net.minecraft.server.v1_7_R1.EntityArrow;
+
+import org.bukkit.craftbukkit.v1_7_R1.CraftServer;
+import org.bukkit.craftbukkit.v1_7_R1.entity.CraftArrow;
+import org.bukkit.entity.Vehicle;
+
+public class VehicleArrow extends CraftArrow implements Vehicle {
+
+	public VehicleArrow(CraftServer server, EntityArrow entity) 
+	{
+		super(server, entity);
+	}
+	
+	@Override
+	public void remove() 
+	{
+		if (this.getPassenger() == null) 
+		{
+			super.remove();
+		}
+	}
+
+}