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    <p>To answer your question in one sentence:</p> <p><strong>Per default, Maps don't have a last entry, it's not part of their contract.</strong></p> <hr> <p>And a side note: it's good practice to code against interfaces, not the implementation classes (see <a href="http://java.sun.com/docs/books/effective/" rel="noreferrer">Effective Java by Joshua Bloch</a>, Chapter 8, Item 52: <strong>Refer to objects by their interfaces</strong>).</p> <p>So your declaration should read:</p> <pre><code>Map&lt;String,Integer&gt; map = new HashMap&lt;String,Integer&gt;(); </code></pre> <p>(All maps share a common contract, so the client need not know what kind of map it is, unless he specifies a sub interface with an extended contract).</p> <hr> <h2>Possible Solutions</h2> <h3>Sorted Maps:</h3> <p>There is a sub interface <a href="http://download.oracle.com/javase/6/docs/api/java/util/SortedMap.html" rel="noreferrer">SortedMap</a> that extends the map interface with order-based lookup methods and it has a sub interface <a href="http://download.oracle.com/javase/6/docs/api/java/util/NavigableMap.html" rel="noreferrer">NavigableMap</a> that extends it even further. The standard implementation of this interface, <a href="http://download.oracle.com/javase/6/docs/api/java/util/TreeMap.html" rel="noreferrer">TreeMap</a>, allows you to sort entries either by natural ordering (if they implement the <a href="http://download.oracle.com/javase/6/docs/api/java/util/Comparator.html" rel="noreferrer">Comparable</a> interface) or by a supplied <a href="http://download.oracle.com/javase/6/docs/api/java/util/Comparator.html" rel="noreferrer">Comparator</a>.</p> <p>You can access the last entry through the <a href="http://download.oracle.com/javase/6/docs/api/java/util/TreeMap.html#lastEntry()" rel="noreferrer">lastEntry</a> method:</p> <pre><code>NavigableMap&lt;String,Integer&gt; map = new TreeMap&lt;String, Integer&gt;(); // add some entries Entry&lt;String, Integer&gt; lastEntry = map.lastEntry(); </code></pre> <h3>Linked maps:</h3> <p>There is also the special case of <a href="http://download.oracle.com/javase/6/docs/api/java/util/LinkedHashMap.html" rel="noreferrer">LinkedHashMap</a>, a HashMap implementation that stores the order in which keys are inserted. There is however no interface to back up this functionality, nor is there a direct way to access the last key. You can only do it through tricks such as using a List in between:</p> <pre><code>Map&lt;String,String&gt; map = new LinkedHashMap&lt;String, Integer&gt;(); // add some entries List&lt;Entry&lt;String,Integer&gt;&gt; entryList = new ArrayList&lt;Map.Entry&lt;String, Integer&gt;&gt;(map.entrySet()); Entry&lt;String, Integer&gt; lastEntry = entryList.get(entryList.size()-1); </code></pre> <h3>Proper Solution:</h3> <p>Since you don't control the insertion order, you should go with the NavigableMap interface, i.e. you would write a comparator that positions the <code>Not-Specified</code> entry last.</p> <p>Here is an example:</p> <pre><code>final NavigableMap&lt;String,Integer&gt; map = new TreeMap&lt;String, Integer&gt;(new Comparator&lt;String&gt;() { public int compare(final String o1, final String o2) { int result; if("Not-Specified".equals(o1)) { result=1; } else if("Not-Specified".equals(o2)) { result=-1; } else { result =o1.compareTo(o2); } return result; } }); map.put("test", Integer.valueOf(2)); map.put("Not-Specified", Integer.valueOf(1)); map.put("testtest", Integer.valueOf(3)); final Entry&lt;String, Integer&gt; lastEntry = map.lastEntry(); System.out.println("Last key: "+lastEntry.getKey() + ", last value: "+lastEntry.getValue()); </code></pre> <p>Output:</p> <blockquote> <p>Last key: Not-Specified, last value: 1</p> </blockquote> <h3>Solution using HashMap:</h3> <p>If you must rely on HashMaps, there is still a solution, using a) a modified version of the above comparator, b) a <a href="http://download.oracle.com/javase/6/docs/api/java/util/List.html" rel="noreferrer">List</a> initialized with the Map's <a href="http://download.oracle.com/javase/6/docs/api/java/util/Map.html#entrySet()" rel="noreferrer">entrySet</a> and c) the <a href="http://download.oracle.com/javase/6/docs/api/java/util/Collections.html#sort%28java.util.List,%20java.util.Comparator%29" rel="noreferrer">Collections.sort()</a> helper method:</p> <pre><code> final Map&lt;String, Integer&gt; map = new HashMap&lt;String, Integer&gt;(); map.put("test", Integer.valueOf(2)); map.put("Not-Specified", Integer.valueOf(1)); map.put("testtest", Integer.valueOf(3)); final List&lt;Entry&lt;String, Integer&gt;&gt; entries = new ArrayList&lt;Entry&lt;String, Integer&gt;&gt;(map.entrySet()); Collections.sort(entries, new Comparator&lt;Entry&lt;String, Integer&gt;&gt;(){ public int compareKeys(final String o1, final String o2){ int result; if("Not-Specified".equals(o1)){ result = 1; } else if("Not-Specified".equals(o2)){ result = -1; } else{ result = o1.compareTo(o2); } return result; } @Override public int compare(final Entry&lt;String, Integer&gt; o1, final Entry&lt;String, Integer&gt; o2){ return this.compareKeys(o1.getKey(), o2.getKey()); } }); final Entry&lt;String, Integer&gt; lastEntry = entries.get(entries.size() - 1); System.out.println("Last key: " + lastEntry.getKey() + ", last value: " + lastEntry.getValue()); } </code></pre> <p>Output:</p> <blockquote> <p>Last key: Not-Specified, last value: 1</p> </blockquote>
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