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- <section class="sect1" title="Other Java features" epub:type="subchapter" id="Tutorial---Other-Java-features">
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- <h2 class="title" style="clear: both">Other Java features</h2>
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- <h3 id="idm139667880338016">Import</h3>
- <p>The <code class="literal">import</code> form can be used to avoid having to write
- fully-qualified class names. For example:
- </p>
- <pre class="screen">(import (class java.util
- Map
- (HashMap HMap)))
- </pre>
- <p>This defines aliases for two classes in the <code class="literal">java.util</code> package,
- one with renaming:
- <code class="literal">Map</code> is an alias for <code class="literal">java.util.Map</code>,
- and <code class="literal">HMap</code> is an alias for <code class="literal">java.util.HashMap</code>.
- </p>
- <p>The <code class="literal">class</code> keyword is needed because the <code class="literal">import</code>
- form is also used for Kawa’s module system.
- See <a class="link" href="FAQs.xhtml#importing-class-names">importing-class-names</a> and <a class="link" href="Importing.xhtml" title="Importing from a library">Importing</a> for details.
- </p>
- <h3 id="idm139667880330784">Synchronized blocks</h3>
- <p>You can use a <code class="literal">synchronized</code> expression:
- </p>
- <pre class="screen">(synchronized obj form1 ... formn)
- </pre>
- <p>This waits until it can get an exclusive lock on <em class="replaceable"><code>obj</code></em>
- and then evaluates <em class="replaceable"><code>form1</code></em> through <em class="replaceable"><code>formn</code></em>.
- Unlike Java, this is an expression and returns the value of <em class="replaceable"><code>formn</code></em>.
- </p>
- <h3 id="idm139667880326704">Annotations</h3>
- <p>You can write annotation declarations - see <a class="link" href="Annotations.xhtml" title="Annotations of declarations">Annotations</a> for details.
- </p>
- <p>Kawa does not yet support annotations on types,
- or declaring new annotation classes.
- </p>
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