title: Why am I getting the "Class Not Found" error in Java?
body: <p>Upon trying to run my code, I get this problem:</p>
  <pre><code>Exception in thread &quot;main&quot; java.lang.NoClassDefFoundError: org/apache/commons/codec/digest/DigestUtils
      at primjer.ZastitniKodIzracun.main(ZastitniKodIzracun.java:67)
  Caused by: java.lang.ClassNotFoundException: org.apache.commons.codec.digest.DigestUtils
      at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
      at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
      at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
      ... 1 more
  </code></pre>
  <p>If I understood well, this could be due to an error in naming/saving the files which compose the project, but I'm not sure what's the problem - the name of the Java source code file corresponds to the text of the &quot;public class&quot; line in the code (ZastitniKodIzracun.java). I'm working in Eclipse. The beginning of the code goes like this:</p>
  <pre><code>import java.io.FileInputStream;
  import java.security.Key;
  import java.security.KeyStore;
  import java.security.PrivateKey;
  import java.security.Signature;
  import java.util.Date;
  import java.text.SimpleDateFormat;
  import org.apache.commons.codec.digest.DigestUtils;
  </code></pre>