Java Concurrent modification exception

I wrote the following code, resulting in concurrent modification exceptions How can I prevent it? Our idea is to escape all the values of the map and rebuild the object (do) with the new param map

try {
        Map<String,String[]> paramMap = dO.getParameterMap();
        Set<Map.Entry<String,String[]>> entries = paramMap.entrySet();
        Iterator<Map.Entry<String,String[]>> it = entries.iterator();
        while (it.hasNext()) {
            Map.Entry<String,String[]> entry = it.next();
            String[] values = entry.getValue();
            List<String> valList = new ArrayList<String>();
            if (values != null) {
                for (String value : values) {
                    valList.add(escapeHTML(value));
                     }
                dO.removeParameter(entry.getKey());

//Please note that parameter is a HashMap, so do you need to delete the entry before inserting, otherwise it will replace the new value associated with the key How does it work in Java?

dO.addParameter(entry.getKey(),valList.toArray(new String[valList.size()]));
               }
            }
        }

Solution

The exception is thrown because you add / delete the content in the map during iteration:

dO.removeParameter(entry.getKey());
dO.addParameter(entry.getKey(),valList.toArray(new String[valList.size()]

You should use iterator Remove() instead