title: java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory problem
body: <p>I am new to itext7, I am using Eclipse IDE. I downloaded all the itext7 jar files and added it to my libraries (classpath). When I run my program (to convert text file to PDF file), I got the following error:</p>
  <pre><code>Exception in thread &quot;main&quot; java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
  at com.itextpdf.kernel.pdf.PdfPagesTree.&lt;clinit&gt;(PdfPagesTree.java:72)
  at com.itextpdf.kernel.pdf.PdfCatalog.&lt;init&gt;(PdfCatalog.java:99)
  at com.itextpdf.kernel.pdf.PdfCatalog.&lt;init&gt;(PdfCatalog.java:103)
  at com.itextpdf.kernel.pdf.PdfDocument.open(PdfDocument.java:1958)
  at com.itextpdf.kernel.pdf.PdfDocument.&lt;init&gt;(PdfDocument.java:284)
  at com.itextpdf.kernel.pdf.PdfDocument.&lt;init&gt;(PdfDocument.java:265)
  at TextFileToPDF.createPdf(TextFileToPDF.java:59)
  at TextFileToPDF.main(TextFileToPDF.java:84)
  `Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
  at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
  at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
  at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
  ... 8 more
  </code></pre>
  <p>If I add all the jar files to my libraries(ModulePath), then I got the following errors:</p>
  <p>Error: Unable to initialize main class TextFileToPDF
  Caused by: java.lang.NoClassDefFoundError: com/itextpdf/layout/element/IBlockElement</p>
  <p>Does anybody knows how to fix this problem?</p>