How to add one list to another in Java?

Hi,
I have two Lists in Java. I would like to add one list to the other list as I get it from another method.

Basically, the code is like this:
    static List<CheckDetail> checkDetails = null;
    static List<CheckDetail> checkDetailsAll = null;
  
         public static List<CheckDetail> runCheck() throws IOException {

              for (int j = 0; j < fileData.length; j++){
                
                //SOME CODE IN HERE

                checkDetails = new ParseResultsXML().parse(path2ResultsXML);
                //IN THE NEXT LINE I WANT TO ADD checkDetails list to checkDetailsAll list .               //BUT THIS DOES NOT WORK and 
                //I GET java.lang.NullPointerException FOR THE NEXT LINE
                checkDetailsAll.addAll(checkDetails);
             }

            return checkDetailsAll;
        }

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Can you please help?
TolgarAsked:
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CEHJCommented:
//I GET java.lang.NullPointerException FOR THE NEXT LINE
Because you didn't initialize this:

static List<CheckDetail> checkDetailsAll = null;

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TolgarAuthor Commented:
Thanks a lot again!
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CEHJCommented:
:)
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CEHJCommented:
Sorry - i don't do SWT. But i'll give some thought to your batch file question
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TolgarAuthor Commented:
Thanks!
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