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copied!<p>Let's go over <em>cloning</em> step by step:</p> <ul> <li><p>Although, every object inherits <code>Object.clone()</code>, cloning is <strong>not</strong> ON by default. That means if you try to <code>clone()</code> some random object you would probably get a <strong><em>CloneNotSupportedException</em></strong>.</p></li> <li><p>To <em>enable</em> cloning, an object's class or one of it's super classes must implement <strong><em>Cloneable</em></strong> interface. It's just a <em>marker</em> interface without which the exception mentioned above would get thrown.</p></li> <li><p>Assuming cloning has been enabled, the default implementation is inherited as <strong><em>protected</em></strong>. So, the class can still use it to create its object's copies but it cannot be called by the public yet.</p></li> <li><p>Now, if your class wants to provide for making copies of its objects from outside of the class it can <em>override</em> <code>Object.clone()</code> as <strong><em>public</em></strong> and simply call <code>super.clone()</code> inside to still use the default implementation.</p></li> <li><p>Which brings me to the last point. The <strong>default implementation</strong> is to make a <em>shallow-copy</em> of the object which means it would simply copy all the primitives as well as reference values on to the new object. This means, complex data structures, like a <code>Map</code> would get shared since both the copies though would have two different references but they would be pointing to the same <code>Map</code>.<br /><br /> This is why an <em>override</em> most of the times has to provide its own implementation to make (what is better known as) a <em>deep-copy</em> of the object so that the clone is not sharing any state from its source object and can be modified independently without affecting other's state.</p></li> </ul>

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