public static String[] parseKey(String groupKey) {
        StringBuilder sb = new StringBuilder();
        String dataId = null;
        String group = null;
        String tenant = null;
        
        for (int i = 0; i < groupKey.length(); ++i) {
            char c = groupKey.charAt(i);
            if ('+' == c) {
                if (null == dataId) {
                    dataId = sb.toString();
                    sb.setLength(0);
                } else if (null == group) {
                    group = sb.toString();
                    sb.setLength(0);
                } else {
                    throw new IllegalArgumentException("invalid groupkey:" + groupKey);
                }
            } else if ('%' == c) {
                char next = groupKey.charAt(++i);
                char nextnext = groupKey.charAt(++i);
                if ('2' == next && 'B' == nextnext) {
                    sb.append('+');
                } else if ('2' == next && '5' == nextnext) {
                    sb.append('%');
                } else {
                    throw new IllegalArgumentException("invalid groupkey:" + groupKey);
                }
            } else {
                sb.append(c);
            }
        }
        
        if (StringUtils.isBlank(group)) {
            group = sb.toString();
        } else {
            tenant = sb.toString();
        }
        if (group.length() == 0) {
            throw new IllegalArgumentException("invalid groupkey:" + groupKey);
        }
    
        return new String[] {dataId, group, tenant};
    }
@Test
    void testParseKeyForInvalidStringIndexOutOfBoundsException() {
        assertThrows(StringIndexOutOfBoundsException.class, () -> {
            GroupKey.parseKey("++%");
            
            // Method is not expected to return due to exception thrown
        });
        
        // Method is not expected to return due to exception thrown
    }