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copied!<p>There is a difference. The first will be treated as </p> <pre><code>Integer I = Integer.valueOf(30); // autoboxing </code></pre> <p>which will use an <code>Integer</code> object already stored in an internal cache (this is true when autoboxing values in the range -127 to 128 inclusive). The second will explicitly create a <em>new</em> <code>Integer</code> object.</p> <p>You can see this for yourself:</p> <pre><code>Integer I1 = 30; Integer I2 = 30; System.out.println(I1 == I2); </code></pre> <pre> true </pre> <p>vs</p> <pre><code>Integer I1 = new Integer(30); Integer I2 = new Integer(30); System.out.println(I1 == I2); </code></pre> <pre> false </pre> <p>In general don't compare <code>Integer</code> objects with <code>==</code> since that tests for reference equality. I was using it here to test if <code>I1</code> and <code>I2</code> refer to the same instance. In the first snippet, they do because the <code>Integer</code> corresponding to the <code>int</code> <code>30</code> already exists in a cache, and this instance is used and assigned to both <code>I1</code> and <code>I2</code>. In the second snippet, they do not since we are creating two independent objects via <code>new</code>.</p> <p>By the way there is no autoboxing involved in the second case, you're just creating a simple new object. There is autoboxing in the first case because an <code>int</code> is being implicitly converted to an <code>Integer</code>.</p> <p>You can actually see the effects of autoboxing by viewing the compiled bytecode with <code>javap -c MyClass</code>.</p>

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