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<TITLE>Storing Primitive Types in a Collection (Java Developers Almanac Example)
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  <h3>e346. Storing Primitive Types in a Collection</h3>

Collections can only store objects, not primitive types like <code>int</code>
and <code>double</code>.  Primitive types must be placed in a <font color="#0066ff"><i>wrapper</i></font>
object before they can be placed in a collection.  This example
demonstrates the storing of <code>int</code> values in a <code>Map</code>.

<P> See also: <a href="../java.lang/Wrap.html" class="eglink"><b>e58</b> Wrapping a Primitive Type in a Wrapper Object</a>.


<pre>    // Create map
    Map map = new HashMap();
    
    // Create int wrapper object
    Integer refInt = new Integer(<font color="#0066ff"><i>123</i></font>);
    
    // Store int in map
    map.put(<font color="#0066ff"><i>"key"</i></font>, refInt);
    
    // Get int value from map
    refInt = (Integer)map.get(<font color="#0066ff"><i>"key"</i></font>);
    
    // Get the integer value from wrapper object
    int i = refInt.intValue();
</pre>
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            &nbsp;<b>Related Examples</b></font></td>
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e342. <a class="eglink" href="coll_Queue.html?l=rel">
    Implementing a Queue
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e343. <a class="eglink" href="coll_Stack.html?l=rel">
    Implementing a Stack
</a>
<br>

e344. <a class="eglink" href="coll_Cache.html?l=rel">
    Implementing a Least-Recently-Used (LRU) Cache
</a>
<br>

e345. <a class="eglink" href="coll_Iterate.html?l=rel">
    Listing the Elements of a Collection
</a>
<br>

e347. <a class="eglink" href="coll_CreateCopy.html?l=rel">
    Creating a Copy of a Collection
</a>
<br>

e348. <a class="eglink" href="coll_MakeRo.html?l=rel">
    Making a Collection Read-Only
</a>
<br>


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        See also: 
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    Bits
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    Property Files
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<a class="eglink" href="/egs/java.util/pkg.html?l=rel#Sets">
    Sets
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<a class="eglink" href="/egs/java.util/pkg.html?l=rel#Sorted%20Collections">
    Sorted Collections
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<a class="eglink" href="/egs/java.util/pkg.html?l=rel#Time">
    Time
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