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copied!<p>You can use the <code>ClassLoader.findLoadedClass()</code> method. If it returns null, then the class isn't loaded. This way you don't load the class if it wasn't already loaded.</p> <hr> <p><strong>WARNING</strong> : This code doesn't really work here, in the system ClassLoader, <code>findLoadedClass()</code> is protected, you need to override it with your own ClassLoader.</p> <p><em>Check the link below <strong>On the same topic</strong> to check if a class is loaded with the system ClassLoader</em></p> <pre><code>if(ClassLoader.getSystemClassLoader().findLoadedClass("java.lang.String") != null){ System.out.println("Yepee, String is loaded !"); } </code></pre> <hr> <p>Very good point from @irreputable :</p> <blockquote> <p>"loaded" doesn't mean "initialized". initialization only happens at precise moments defined by JLS3 $12.4.1 </p> </blockquote> <p>And I quote :</p> <blockquote> <p>A class or interface type <em>T</em> will be initialized immediately before the first occurrence of any one of the following:</p> <ul> <li><em>T</em> is a class and an instance of <em>T</em> is created.</li> <li><em>T</em> is a class and a static method declared by <em>T</em> is invoked.</li> <li>A static field declared by <em>T</em> is assigned.</li> <li>A static field declared by <em>T</em> is used and the field is not a constant variable <a href="http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#10931" rel="nofollow noreferrer">(§4.12.4)</a>.</li> <li><em>T</em> is a top-level class, and an <code>assert</code> statement <a href="http://java.sun.com/docs/books/jls/third_edition/html/statements.html#35518" rel="nofollow noreferrer">(§14.10)</a> lexically nested within <em>T</em> is executed.</li> </ul> <p>Invocation of certain reflective methods in class <code>Class</code> and in package <code>java.lang.reflect</code> also causes class or interface initialization. A class or interface will not be initialized under any other circumstance.</p> </blockquote> <hr> <p><strong>Resources :</strong></p> <ul> <li><a href="http://download.oracle.com/javase/6/docs/api/java/lang/ClassLoader.html#findLoadedClass(java.lang.String)" rel="nofollow noreferrer">Javadoc - <code>ClassLoader.findLoadedClass()</code></a></li> <li><a href="http://onjava.com/pub/a/onjava/2005/01/26/classloading.html" rel="nofollow noreferrer">Internals of Java Class Loading</a></li> <li><a href="http://java.sun.com/docs/books/jls/third_edition/html/execution.html#12.4.1" rel="nofollow noreferrer">JLS - §12.4.1 When Initialization Occurs</a></li> </ul> <p><strong>On the same topic :</strong></p> <ul> <li><a href="https://stackoverflow.com/questions/482633/in-java-is-it-possible-to-know-whether-a-class-has-already-been-loaded">In Java, is it possible to know whether a class has already been loaded?</a></li> </ul>

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