title: IntelliJ IDEA: ClassNotFoundException if run Debug, execution/run does work
body: <p>I have a Java Maven Project started in Eclipse, worked on it a few days, then imported it in IntelliJ IDEA, again working on it a few days. </p>
  
  <p>The normal Run/Execution in IDEA and via shell does work, but not the Debug. </p>
  
  <p>When I click the Bug Icon for Debug, it opens up URLClassLoader.java file and points on the Line "throw new ClassNotFoundException(name)" and pauses the Debug, if I click Resume Debug, it shows several Classes that do not belong to my project. I can click the Resume Button endless, it shows the same classes, also ClassNotFoundException over and over again in a continuously loop and does not debug my source.</p>
  
  <p>If I click Build -> Rebuild Project it says at the Debug icon
  "Hot Swap failed
  myClassname: schema change not implemented;
  myClassname: Operation not supported by VM"</p>
  
  <p>In the Debug window under Variables it says: "Frame is not available"</p>
  
  <p>The Debug of this project in IntelliJ IDEA did work previously, whats wrong now?</p>