[java] Accessing the last entry in a Map

How to move a particular HashMap entry to Last position?

For Example, I have HashMap values like this:

HashMap<String,Integer> map = new HashMap<String,Integer>();

map= {Not-Specified 1, test 2, testtest 3};

"Not-Specified" may come in any position. it may come first or in the middle of the map. But i want to move the "Not-Specified" to the last position.

How can I do that? thanks in advance.

Find missing all elements from array
        int[] array = {3,5,7,8,2,1,32,5,7,9,30,5};
        TreeMap<Integer, Integer> map = new TreeMap<>();
        for(int i=0;i<array.length;i++) {
            map.put(array[i], 1);
        }
        int maxSize = map.lastKey();
        for(int j=0;j<maxSize;j++) {
            if(null == map.get(j))
                System.out.println("Missing `enter code here`No:"+j);
        }

When using numbers as the key, I suppose you could also try this:

        Map<Long, String> map = new HashMap<>();
        map.put(4L, "The First");
        map.put(6L, "The Second");
        map.put(11L, "The Last");

        long lastKey = 0;
        //you entered Map<Long, String> entry
        for (Map.Entry<Long, String> entry : map.entrySet()) {
            lastKey = entry.getKey();
        }
        System.out.println(lastKey); // 11

A SortedMap is the logical/best choice, however another option is to use a LinkedHashMap which maintains two order modes, most-recently-added goes last, and most-recently-accessed goes last. See the Javadocs for more details.

In such scenario last used key is usually known so it can be used for accessing last value (inserted with the one):

class PostIndexData {
    String _office_name;
    Boolean _isGov;
    public PostIndexData(String name, Boolean gov) {
        _office_name = name;
        _isGov = gov;
    }
}
//-----------------------
class KgpData {
    String _postIndex;
    PostIndexData _postIndexData;
    public KgpData(String postIndex, PostIndexData postIndexData) {
        _postIndex = postIndex;
        _postIndexData = postIndexData;;
    }
}

public class Office2ASMPro {
    private HashMap<String,PostIndexData> _postIndexMap = new HashMap<>();
    private HashMap<String,KgpData> _kgpMap = new HashMap<>();
...
private void addOffice(String kgp, String postIndex, String officeName, Boolean gov) {
            if (_postIndexMap.get(postIndex) == null) {
                _postIndexMap.put(postIndex, new PostIndexData(officeName, gov));
            }
            _kgpMap.put( kgp, new KgpData(postIndex, _postIndexMap.get(postIndex)) );
        }

HashMap doesn't have "the last position", as it is not sorted.

You may use other Map which implements java.util.SortedMap, most popular one is TreeMap.

move does not make sense for a hashmap since its a dictionary with a hashcode for bucketing based on key and then a linked list for colliding hashcodes resolved via equals. Use a TreeMap for sorted maps and then pass in a custom comparator.