Possible null pointer dereference in SONAR

问题

I have tried to point critical issues in Sonar with the following code:

if (candidate.isDirectory() && candidate.canRead() && 
          TEMPLATE.equalsIgnoreCase(candidate.getName())) {  
  List<String> fileContentList = Arrays.asList(candidate.list());

I have also done the change below, but it still didn't work

if(null != Arrays.asList(candidate.list())){
  List<String> fileContentList = Arrays.asList(candidate.list());}

Please help.

回答1:

The error occures because candidate can be null. See https://www.owasp.org/index.php/Null_Dereference for a description.

You could do sth. like this:

List<String> fileContentList = candidate != null ? Arrays.asList(candidate.list()) : new ArrayList<>();

来源：https://stackoverflow.com/questions/37295215/possible-null-pointer-dereference-in-sonar