code: public static String OSX_DOCK_ICON(MinecraftDirectory minecraftDir, Version version) throws IOException {
  		Set<Asset> assetIndex = Versions.resolveAssets(minecraftDir, version);
  		if (assetIndex == null)
  			return null;
  
  		return OSX_DOCK_ICON(minecraftDir, assetIndex);
  	}
docs: Caution: This option is available only on OSX.
  
  @param minecraftDir the minecraft directory
  @param version the minecraft version
  @return a <code>-Xdock:icon</code> option, null if the assets cannot be resolved
  @throws IOException if an I/O error has occurred during resolving asset index
  @see #OSX_DOCK_ICON(MinecraftDirectory, Set)
  @see #OSX_DOCK_NAME