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<p>The @Newify transformation proposes two new ways of instantiating classes.     The first one is providing Ruby like approach to creating instances with a new() class method:</p>
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@Newify rubyLikeNew() {
    assert Integer.new(42) == 42
}

rubyLikeNew()
</pre></td></tr></table>
<p>But it is also possible to follow the Python approach with omitting the new keyword.     Imagine the following tree creation:</p>
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class Tree {
    def elements
    Tree(Object... elements) { this.elements = elements as List }
}

class Leaf {
    def value
    Leaf(value) { this.value = value }
}

def buildTree() {
    new Tree(new Tree(new Leaf(1), new Leaf(2)), new Leaf(3))
}

buildTree()
</pre></td></tr></table>
<p>The creation of the tree is not very readable because of all those new keywords spread across the line.     The Ruby approach wouldn't be more readable, since a new() method call for creating each element is needed.     But by using @Newify, we can improve our tree building slightly to make it easier on the eye:</p>
<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
@Newify([Tree, Leaf]) buildTree() {
    Tree(Tree(Leaf(1), Leaf(2)), Leaf(3))
}
</pre></td></tr></table>
<p>You'll also notice that we just allowed Tree and Leaf to be <em>newified</em>.     By default, under the scope which is annotated, all instantiations are <em>newified</em>, but you can limit the reach by specifying the classes you're interested in. Also, note that for our example, perhaps a Groovy builder may have been more appropriate, since its purpose is to indeed create any kind of hierarchical / tree strucutre.</p>

<p>If we take another look at our coordinates example from a few sections earlier,      using both @Immutable and @Newify can be interesting for creating a path with a concise but type-safe manner:</p>
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@Immutable final class Coordinates {
    Double latitude, longitude
}

@Immutable final class Path {
    Coordinates[] coordinates
}

@Newify([Coordinates, Path])
def build() {
    Path(
        Coordinates(48.824068, 2.531733),
        Coordinates(48.857840, 2.347212),
        Coordinates(48.858429, 2.342622)
    )
}

assert build().coordinates.size() == 3
</pre></td></tr></table>
<p>A closing remark here: since a Path(Coordinates[] coordinates) was generated, we can use that constructor in a <em>varargs way</em> in Groovy,     just as if it had been defined as Path(Coordinates... coordinates).</p>