How can I sort a ConcurrentHashMap by values?

Question

ConcurrentHashMap pl = new ConcurrentHashMap<>();
pl.put(\"joker25\", 255);
pl.put(\"minas\", 55);
pl.put(\"agoriraso\", 122);
pl.put(\"p         


        

Answer 1

Since ConcurrentHashMap makes no guarantees about ordering you'll have to dump the items into a list and then sort that. For example:

final Map pl = ....
List values = new ArrayList<>(pl.keySet());
Collections.sort(values, new Comparator() {
  public int compare(String a, String b) {
    // no need to worry about nulls as we know a and b are both in pl
    return pl.get(a) - pl.get(b);
  }
});

for(String val : values) {
  System.out.println(val + "," + pl.get(val));
}