Avoiding TreeMap ConcurrentModificationException?

Question

I am calling function that returns TreeMap instance, and in the calling code I wanted to modify the TreeMap. However, I am getting a ConcurrentModificationException.

Here is my code:

public Map<String, String> function1() {
    Map<String, String> key_values = Collections.synchronizedMap(new TreeMap<String, String>());
    // all key_values.put() goes here

    return key_values;
}

And my calling code is:

Map<String, String> key_values =Collections.synchronizedMap(Classname.function1());
//here key_values.put() giving ConcurrentModificationException

Answer 1

If you use a ConcurrentSkipListMap is can be faster and doesn't have this issue.

public NavigableMap<String, String> function1() {
    NavigableMap<String, String> key_values = new ConcurrentSkipListMap<String, String>();
    // all key_values.put() goes here

    return key_values;
}

If you don't need the keys to be sorted you can use a ConcurrentHashMap.