public static String join(Collection<?> objectsToJoin, String separator) {
        if ((objectsToJoin != null) && !objectsToJoin.isEmpty()) {
            StringBuilder builder = new StringBuilder();
            for (Object object : objectsToJoin) {
                builder.append(object);
                builder.append(separator);
            }
            // Remove the last separator
            return builder.substring(0, builder.length() - separator.length());
        } else {
            return EMPTY;
        }
    }
public static String join ( Collection < ? > objectsToJoin , String separator ) { if ( ( objectsToJoin != null ) && ! objectsToJoin . isEmpty ( ) ) { StringBuilder builder = new StringBuilder ( ) ; for ( Object object : objectsToJoin ) { builder . append ( object ) ; builder . append ( separator ) ; } return builder . substring ( 0 , builder . length ( ) - separator . length ( ) ) ; } else { return EMPTY ; } }
Joins all the strings in the list in a single one separated by the separator sequence.

@param objectsToJoin The objects to join.
@param separator     The separator sequence.
@return The joined strings.