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    <p>First, a tid bit... calling the constructor of an object does not allocate it. In bytecode, the initialization <code>new Object()</code> is expressed as something to the effect of...</p> <pre><code>new java/lang/Object invokespecial java/lang/Object &lt;init&gt;()V </code></pre> <p>The <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-6.html#jvms-6.5.new" rel="nofollow"><code>new</code></a> instruction takes care of allocating the space and acquiring a reference to the yet <em>uninitialized</em> object, while the <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-6.html#jvms-6.5.invokespecial" rel="nofollow"><code>invokespecial</code></a> handles calling the constructor itself (which is internally compiled to a <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-2.html#jvms-2.9" rel="nofollow"><code>void</code> method named <code>&lt;init&gt;</code></a>, hence the <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.3" rel="nofollow">descriptor</a> <code>&lt;init&gt;()V</code>).</p> <p>Moving on, internals of object allocation and <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-2.html#jvms-2.7" rel="nofollow">representation on the heap are entirely JVM specific</a>. However, as far as I know, there is only <strong>one</strong> allocated object per allocated object, no matter its number of super classes. The object itself in memory has space for the instance fields of both its own class and its super classes. It must also have space for a <a href="http://en.wikipedia.org/wiki/Virtual_method_table" rel="nofollow"><em>virtual method table</em></a>, in order to do virtual dispatch when performing virtual method calls (e.g. via <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.10.1.4.5.invokevirtual" rel="nofollow"><code>invokevirtual</code></a>) for the object.</p> <p>Internally, the Oracle HotSpot JVM manages things called <em>oops</em>, or ordinary object pointers. You can read more about the HotSpot memory layout <a href="https://wikis.oracle.com/display/HotSpotInternals/CompressedOops" rel="nofollow">here</a>. Feel free to <a href="http://hg.openjdk.java.net/jdk7/hotspot/hotspot/" rel="nofollow">browse the HotSpot source repository</a>.</p>
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    1. COAn object's fields are resolved statically, so you can know at compile time exactly how big the full object would be, as well as the offsets for each of its fields. Moreover, each override of a given method always uses the same field offset, since fields are statically resolved. So I don't know of any reason why the JVM would instants ate four objects instead of one.
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    2. COThe compiler does not resolve where fields are in memory, the JVM does... the Java allocates one object in memory and executes the code from the super class constructors from the immediate super class up to `Object` (inside the constructor, it is possible other objects are constructed too e.g. for field initialization).
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