Question

I am getting really tired from this problem, and I do not know what to do.

import ... 
class ...

private ArrayList <Operation> operationList = new ArrayList<Operation>();

@Override
public Collection<String> lineList() {
    Set <String> groupOperation = new HashSet<String>();
    Operace newOperation= null;

    LogFileReader reader = new LogFileReader(nameFile);
    LogEntry line = reader.nextLine();

    while(reader.existsLine()) {
        for(Operation whatever2: operationList) {
            if(line.getOperation().equals(whatever2.getName())) {
                whatever2.setAmmount(whatever2.getAmmount()+1);
                line = reader.nextLine();
            }
        }
        newOperation = new Operation(line.getOperation());
        newOperation.setAmmount(1);
        groupOperation .add(newOperation);
        line = reader.nextLine();
    }
    ....
    return groupOperation;
}

• The problem is in while WITH FOR(x y: z) IF (), other things
  work.

• (If i will delete whole FOR, it seems, that it works, but I need counting.)

• IN THE CLASS OPERATION IS ONLY GETTER AND SETTER for “name” and “ammount”.

  1. Explanation
  2. I read a file.
  3. I read only topic from a file.
  4. I load that like a Operation(name = title, ammount = how many times is the same in file)
  5. I give it to ArrayList = IT DOESNT WORK VERY WELL !!!
  6. From ArrayList to Set, thats to interface.
  7. Interface to GUI.

EDIT1: “Exception in thread “AWT-EventQueue-0″ java.lang.NullPointerException”

I hope anyone will understand,

Thanks to everybody,

MmM …

Answer 1

In your for loop, you have this line:

      line = reader.nextLine();

This doesn’t have any check on line existence as you have done in while condition -> reader.existsLine(). This makes it to read the lines and may fail here or last statement in the while, if there are no more lines to read.

I am not sure, you really want to read the line within the for loop. if yes, wrap in the if condition as:

       if(reader.existsLine()){
          line = reader.nextLine();
       }