SPIGOT-5496: API to create and manipulate hardcore worlds

src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -910,7 +910,7 @@ public final class CraftServer implements Server {
                 }
             }
         } while(used);
-        boolean hardcore = false;
+        boolean hardcore = creator.hardcore();
 
         WorldNBTStorage sdm = new WorldNBTStorage(getWorldContainer(), name, getServer(), getHandle().getServer().dataConverterManager);
         WorldData worlddata = sdm.getWorldData();

src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -88,7 +88,6 @@ import net.minecraft.server.Ticket;
 import net.minecraft.server.TicketType;
 import net.minecraft.server.Unit;
 import net.minecraft.server.Vec3D;
-import net.minecraft.server.WorldGenFeatureEmptyConfiguration;
 import net.minecraft.server.WorldGenerator;
 import net.minecraft.server.WorldServer;
 import org.apache.commons.lang.Validate;
@@ -1880,6 +1879,16 @@ public class CraftWorld implements World {
         return world.getWorldData().shouldGenerateMapFeatures();
     }
 
+    @Override
+    public boolean isHardcore() {
+        return world.getWorldData().isHardcore();
+    }
+
+    @Override
+    public void setHardcore(boolean hardcore) {
+        world.getWorldData().g(hardcore);
+    }
+
     @Override
     public long getTicksPerAnimalSpawns() {
         return world.ticksPerAnimalSpawns;