common/src/main/java/org/jboss/pnc/common/util/StringUtils.java
public static String addEndingSlash(String string) {
        if (string == null) {
            return null;
        }
        if (!string.endsWith("/")) {
            string += "/";
        }
        return string;
    }
public static String addEndingSlash(String string) {
        if (string == null) {
            return null;
        }
        if (!string.endsWith("/")) {
            string += "/";
        }
        return string;
    }
Adds ending slash if it is not present.

@param string
@return