title: Why is Eclipse resolving org.apache.log4j.Level as java.util.logging.Level?
body: <p>Can somebody answer me what's going on here below?
  <img src="https://i.stack.imgur.com/A9PpJ.png" alt="org.apache.log4j.Level"></p>
  
  <p>I am using a decompiler plugin, called JD-Core. Is it messing up class resolution? Or what?</p>
  
  <p>Now I can't run my application neither because of this bug. I build my application as a Maven project, and Maven builds the jar file without any problem. I can also run the app from command line.</p>
  
  <p>Any thoughts on this? Please find the Eclipse console stacktrace below:</p>
  
  <pre><code>
      Failed to instantiate SLF4J LoggerFactory
      Reported exception:
      java.lang.NoClassDefFoundError: org/apache/log4j/Level
          at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)
          at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)
          at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)
          at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)
          at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:288)
          at com.rakuten.gep.sitemap.setup.Configuration.(Configuration.java:21)
          at com.rakuten.gep.sitemap.main.Main.(Main.java:22)
          at com.rakuten.gep.sitemap.main.Main.main(Main.java:29)
      Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level
          at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
          at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
          at java.security.AccessController.doPrivileged(Native Method)
          at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
          at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
          ... 8 more
      Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Level
          at org.slf4j.LoggerFactory.bind(LoggerFactory.java:129)
          at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:108)
          at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:302)
          at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:276)
          at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:288)
          at com.rakuten.gep.sitemap.setup.Configuration.(Configuration.java:21)
          at com.rakuten.gep.sitemap.main.Main.(Main.java:22)
          at com.rakuten.gep.sitemap.main.Main.main(Main.java:29)
      Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Level
          at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
          at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
          at java.security.AccessController.doPrivileged(Native Method)
          at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
          at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
          ... 8 more
  </code></pre>
  
  <hr>
  
  <p>[EDIT]</p>
  
  <p>OK, following this link I could solve my problem:</p>
  
  <p><a href="https://stackoverflow.com/questions/2233656/strange-java-lang-noclassdeffounderror-in-eclipse">Deleting the workspace solves the strange error</a></p>
  
  <p>The third comment in the answer of @rmtheis suggests deleting the whole workspace. I stil don't know why is this needed, and how does it solve the issue, but now everything works fine.</p>