<ul data-eligibleForWebStory="false"><li>The 'Exception in thread 'main' java.lang.NoClassDefFoundError: HelloWorldApp' error occurs when attempting to run a Java program from the command line, often due to missing .class files or incorrect classpath settings.</li><li>This error is typically seen in Java versions up to Java 6; in Java 7 or higher, a similar error message is displayed as 'Error: could not find or load class HelloWorldApp.'</li><li>The solution for both errors is usually the same, involving verifying the presence of the .class file and correcting the classpath settings.</li><li>This issue is common when running Java, Unix, Tibco RV, and FIX Protocol tutorials.</li></ul>

How to Fix Exception in thread "main" java.lang.NoClassDefFoundError: Running Java from Command line

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