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    <p>The list itself is immutable because you cannot add/remove elements. The elements are on their own regarding immutability. In more precise terms, we have definitions from <a href="http://docs.oracle.com/javase/1.4.2/docs/guide/collections/overview.html" rel="nofollow noreferrer">a historical Java 1.4.2 document</a>:</p> <blockquote> <ul> <li>Collections that do not support any modification operations (such as add, remove and clear) are referred to as unmodifiable. Collections that are not unmodifiable are referred to modifiable.</li> <li>Collections that additionally guarantee that no change in the Collection object will ever be visible are referred to as immutable. Collections that are not immutable are referred to as mutable.</li> </ul> </blockquote> <p>Note that for these definitions to make any sense we must assume an implicit distiction between a <em>collection</em> in an abstract sense and an object that <em>represents that collection</em>. This is important because <strong>the object that represents an immutable collection is not itself immutable</strong> by any standard definition of that term. For example, its <code>equals</code> relation has no temporal consistency, a vital requirement on immutable objects.</p> <p>As far as defensive copying, note that is an ill-defined problem in general and there will never be a general immutable collection in Java that will manage to defensively copy its elements. Note additionally that such a collection would be <strong>less useful</strong> than the immutable collections that really exist: when you put an object into a collection, in 99.99% cases you want <strong>that very object</strong> to be there, not some other object that is not even <em>equal</em> to it.</p> <p>There is a quite standard definition of <em>object immutability</em> (as opposed to <em>collection immutability</em>) which assumes transitive immutability of the whole object graph reachable from the immutable object. Taken too literally, though, such a definition will almost never be satisfied in the real world. Two cases in point:</p> <ul> <li><strong>nothing is immutable</strong> in the face of reflection. Even <code>final</code> fields are writable.</li> <li>even <code>String</code>, that bastillon of immutability, <a href="https://stackoverflow.com/questions/11146255/how-to-create-mutable-java-lang-string">has been proven mutable</a> outside the Java sandbox (without a <code>SecurityManager</code>&mdash;which covers 99% of real-world Java programs).</li> </ul>
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    1. POIs guava's ImmutableXXX really immutable?
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    1. COthank you for your answer and well I really do not want to rain on your parade, but to me, this is first obvious from the code, second without any sense at all. If you drop the List word at all and think about it as a *ObjectHolder* and I want to make this Holder immutable, then the object itself has to "immutabilized", I need a copy of it that is only mine. This guy over here (where I got the example from) seems to have the same opinion, and he is not an ordinary guy at all: http://jeremymanson.blogspot.com/2008/04/immutability-in-java.html
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    2. COYour question "why are they called immutable" is answered to the best of my ability. Your rant in the comment above goes more towards a critique of the Java language, but has nothing to do with your question.
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    3. COMy rant? :) I am by any means not trying to be aggressive and if I induced that then I am truly sorry. Your edit makes more sense - it was the same I had in mind, just wanted a confirmation. So to guava *immutable* is actually more *unmodifiable*. Thank you for your time
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