When launching an applet, you may see multiple FileNotFound exceptions in the WebSphere® Application Server logs. These exceptions are harmless and you can safely ignore them.
If the FileNotFound exceptions occur frequently and you want to avoid having them show up in the SystemOut.log file, set the custom property on the WebSphere Application Server Web Container to false, as follows:
com.ibm.ws.webcontainer.modifiedfilenotfoundexceptionbehavior=false