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PO
 

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  1. PO
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    <p>You should use primitive types unless you need an object .<br> wrapper class can be <code>null</code> but primitive types Ex: <code>Integer</code> can be <code>null</code>, <code>int</code> can't. </p> <p>This is <a href="http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html" rel="nofollow">primitive data type</a> initialization : </p> <pre><code>int pInt = 500; </code></pre> <p>This is creating wrapper class for same primitive data type:</p> <pre><code>Integer wInt = new Integer(pInt); </code></pre> <p><strong>The <a href="http://en.wikipedia.org/wiki/Primitive_wrapper_class" rel="nofollow">wrapper classes</a> in the Java API serve two primary purposes:</strong> </p> <ul> <li>To provide a mechanism to “wrap” primitive values in an object so that the primitives can be included in activities reserved for objects, like as being added to Collections, or returned from a method with an object return value.</li> <li>To provide an assortment of utility functions for primitives. Most of these functions are related to various conversions: converting primitives to and from String objects, and converting primitives and String objects to and from different bases (or radix), such as binary, octal, and hexadecimal.</li> </ul> <p>In <strong>Java 1.5</strong> there is one concept called <a href="http://docs.oracle.com/javase/1.5.0/docs/guide/language/autoboxing.html" rel="nofollow">Autoboxing</a>. It has a capability to convert or cast between object wrapper and it's primitive type.</p> <p>SO that means: </p> <pre><code>Integer wInt = 500; int pInt = new Integer(500); </code></pre> <p>It can be possible due to Autoboxing.</p>
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    1. POWhat is the main difference between primitive type and wrapper class?
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    1. USSumit Singh
    1. USSumit Singh
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    1. VO
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      1. VTUpMod
    1. COI think wrapper class can't be null. Otherwise NullExceptionPointer will be thrown!
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      1. USBernard
    2. COInteger can be null
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      1. USSumit Singh
    3. COObject references can be null - thus an object reference to an Integer object can also be null. But if you try to use a null-reference you'll likely get a NullPointerException. Don't treat objects, classes and variables as if they're the same.
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      1. USGimby
 

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