{"action":"opened","issue":{"url":"https://api.github.com/repos/checkstyle/checkstyle/issues/1124","labels_url":"https://api.github.com/repos/checkstyle/checkstyle/issues/1124/labels{/name}","comments_url":"https://api.github.com/repos/checkstyle/checkstyle/issues/1124/comments","events_url":"https://api.github.com/repos/checkstyle/checkstyle/issues/1124/events","html_url":"https://github.com/checkstyle/checkstyle/issues/1124","id":79985075,"number":1124,"title":"MutableException check fails with NPE if extended class is in canonical form","user":{"login":"mkordas","id":5467276,"avatar_url":"https://avatars.githubusercontent.com/u/5467276?v=3","gravatar_id":"","url":"https://api.github.com/users/mkordas","html_url":"https://github.com/mkordas","followers_url":"https://api.github.com/users/mkordas/followers","following_url":"https://api.github.com/users/mkordas/following{/other_user}","gists_url":"https://api.github.com/users/mkordas/gists{/gist_id}","starred_url":"https://api.github.com/users/mkordas/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mkordas/subscriptions","organizations_url":"https://api.github.com/users/mkordas/orgs","repos_url":"https://api.github.com/users/mkordas/repos","events_url":"https://api.github.com/users/mkordas/events{/privacy}","received_events_url":"https://api.github.com/users/mkordas/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-05-23T23:31:35Z","updated_at":"2015-05-23T23:31:35Z","closed_at":null,"body":"[MutableException](http://checkstyle.sourceforge.net/config_design.html#MutableException) check fails with `NullPointerException` if extended class is in canonical form.\r\n\r\n#### Configuration\r\n```xml\r\n<module name=\"MutableException\"/>\r\n```\r\n#### Input file\r\n```java\r\nclass CustomException extends java.lang.Exception {}\r\n```\r\n#### Stacktrace\r\n```\r\njava.lang.NullPointerException\r\n        at com.puppycrawl.tools.checkstyle.checks.design.MutableExceptionCheck.isExtendedClassNamedAsException(MutableExceptionCheck.java:155)\r\n        at com.puppycrawl.tools.checkstyle.checks.design.MutableExceptionCheck.visitClassDef(MutableExceptionCheck.java:114)\r\n        at com.puppycrawl.tools.checkstyle.checks.design.MutableExceptionCheck.visitToken(MutableExceptionCheck.java:91)\r\n        at com.puppycrawl.tools.checkstyle.TreeWalker.notifyVisit(TreeWalker.java:393)\r\n        at com.puppycrawl.tools.checkstyle.TreeWalker.processIter(TreeWalker.java:482)\r\n        at com.puppycrawl.tools.checkstyle.TreeWalker.walk(TreeWalker.java:322)\r\n        at com.puppycrawl.tools.checkstyle.TreeWalker.processFiltered(TreeWalker.java:195)\r\n        at com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck.process(AbstractFileSetCheck.java:76)\r\n        at com.puppycrawl.tools.checkstyle.Checker.process(Checker.java:260)\r\n```"}}