The video tutorial explains the role of class loaders in Java, which are responsible for loading classes needed by a Java program. It describes three types of classes: those written by programmers, those provided by frameworks, and system classes. The tutorial details three types of class loaders: system, extension, and bootstrap, each with specific search paths. The system class loader searches the classpath, the extension class loader searches the extension directory, and the bootstrap class loader loads core Java files. The order of class loader execution is system, extension, and bootstrap. If a class is not found, a 'class not found' exception is thrown.

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