code: private static String concat(char delim, String... parts) {
  		StringBuilder builder = new StringBuilder(parts[0]);
  		for (int i = 1; i < parts.length; ++i) {
  			builder.append(delim).append(parts[i]);
  		}
  		return builder.toString();
  	}
docs: Strings concatenation with a delimeter string. Similar to
  {@link com.dell.doradus.common.Utils#concatenate(String[], String)}
  but uses variable number of arguments instead of array of strings.
  
  @param delim	Strings separator
  @param parts	Strings to concatenate
  @return		Concatenated string