src/main/java/com/simpligility/maven/plugins/android/phase09package/AarMojo.java
protected String endWithSlash( String prefix )
    {
        prefix = StringUtils.defaultIfEmpty( prefix, "/" );
        if ( ! prefix.endsWith( "/" ) )
        {
            prefix = prefix + "/";
        }
        return prefix;
    }
protected String endWithSlash( String prefix )
    {
        prefix = StringUtils.defaultIfEmpty( prefix, "/" );
        if ( ! prefix.endsWith( "/" ) )
        {
            prefix = prefix + "/";
        }
        return prefix;
    }
Makes sure the string ends with "/"

@param prefix any string, or null.
@return the prefix with a "/" at the end, never null.