String cannot be added to List using Object in Java

Question

I am working on a JSF based Web Application where I read contents from a file(dumpfile) and then parse it using a logic and keep adding it to a list using an object and also set a string using the object. But I keep getting this error. I am confused where I am wrong. I am a beginner so can anyone be kind enough to help me?

List<DumpController> FinalDumpNotes;
public List<DumpController> initializeDumpNotes()
throws SocketException, IOException {
PostProcessedDump postProcessedDump = (PostProcessedDump) FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("postProcessedDump");
List<DumpController> FinalNotes = new ArrayList<>();
if (postProcessedDump.getDumpNotes() == null) {
dumpNotes = new DumpNotes();
}
DumpListController dlcon = (DumpListController) FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("dumpListController");
DumpInfo dumpinfo = dlcon.getSelectedDumpInfo();
String fileName = dumpinfo.getDate() + dumpinfo.getTime() + dumpinfo.getSeqNo() + dumpinfo.getType() + dumpinfo.getTape() + dumpinfo.getDescription() + ".txt";
if (checkFileExistsInWin(fileName)) {
postProcessedDump.setDumpnotescontent(getFileContentsFromWin(fileName));
String consolidateDumpnotes = getFileContentsFromWin(fileName);
String lines[];
String content = "";
lines = consolidateDumpnotes.split("\\r?\\n");
List<String> finallines = new ArrayList<>();
int k = 0;
for (int i = 0; i < lines.length; i++) {
if (!lines[i].equalsIgnoreCase("")) {
finallines.add(lines[i]);
k++;
}
}
for (int j = 0; j < finallines.size(); j++) {
if (finallines.get(j).startsWith("---------------------SAVED BY")) {
PostProcessedDump dump = new PostProcessedDump();
dump.setDumpMessage(content);
content = "";
FinalDumpNotes.add(dump);
} else {
content = content + finallines.get(j);
}
}
}
FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("postProcessedDump", postProcessedDump);
return FinalDumpNotes;
}

I get the following error: enter image description here

because they are not from same type!your FinalDumpNotes is a collection of DumpController and your dump is PostProcessedDump. — Lrrr
– Lrrr, Commented Jun 7, 2015 at 15:15
Did you actually take a picture of your monitor to provide that screenshot? That kinda cheers me up :) — Zhedar
– Zhedar, Commented Jun 7, 2015 at 16:55

Elliott Frisch · Accepted Answer · 2015-06-07 15:16:19Z

1

If you want to add instances of type PostProcessedDump to your List you should change it's type. Also, don't forget to initialize it. Something like,

List<PostProcessedDump> FinalDumpNotes = new ArrayList<>();

Also, Java naming convention is to start variable names with a lower case letter. FinalDumpNotes looks like a class, I would suggest something like

 List<PostProcessedDump> processedList = new ArrayList<>();

answered Jun 7, 2015 at 15:16

Elliott Frisch

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Comments

Tim Biegeleisen · Accepted Answer · 2015-06-07 15:18:30Z

1

Problems with your code:

List<DumpController> FinalDumpNotes;

You declare FinalDumpNotes to be a List of DumpController objects, but you never initialize it. In addition, your IDE is barfing on the following line of code:

FinalDumpNotes.add(dump);

because you are attempting to add a PostProcessedDump object to the List instead of a DumpController object.

For starters, you need to initialize your list like this:

List<DumpController> finalDumpNotes = new ArrayList<DumpController>();

Notice that I have made the variable name beginning with lower case, which is the convention (upper case is normally reserved for classes and interfaces).

I will leave it to you as a homework assignment to sort out the correct usage of this List.

answered Jun 7, 2015 at 15:18

Tim Biegeleisen

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2 Comments

Hello Man Over a year ago

I replaced my line with yours and still same error persists

Tim Biegeleisen Over a year ago

Your code is in a mess. The answers given here explain the error you were seeing in your IDE.

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