I keep getting 'Exception in thread "main" java.lang.NullPointerException'

Question

The errors are with the writeToFile() method. I can comment it out and it runs perfectly without the Exception error. So basically, I'm trying to get those Nutrition facts to print on a text file. The error looks like this

"Exception in thread "main" java.lang.NullPointerException at Environment.writeToFile(Java1001.java:71) at Environment.(Java1001.java:54) at Java1001.main(Java1001.java:43)"

 import static java.lang.System.*;
    import java.io.*;

    public class Java1001
    {
        public static void main(String[] args) throws IOException
        {
            new Environment();
        } 
    }

    class Environment
    {
        private PrintStream outFile;

        public Environment()
        {
            createOutputStream();
            writeToFile();
        }

        public void createOutputStream()
        {
            // create outFile stream here
            File outFile = null;
            try
            {
                outFile = new File("Nutrition.txt");
                outFile.createNewFile();
            }
            catch (Exception e){}
        }

        public void writeToFile()
        {
            outFile.println("NUTRITION FACTS");
            outFile.println("======================================");
            outFile.println("Serving Size 1 tbsp (6g)");
            outFile.println("Servings Per Container about 4");
            outFile.println("======================================");
            outFile.println("Amount Per Serving");
            outFile.println("Calories           20");
            outFile.println("Calories from Fat  5");
            outFile.println("======================================");
            outFile.println("Total Fat 0.5g");
            outFile.println("Sodium 280mg");
            outFile.println("Total Carbohydrate 4g");
            outFile.println("Sugars 0g");
            outFile.println("Protein less than 1 g");
            outFile.println("======================================");
        }
    }

You are initialising the local variable `outFile` in `createOutputStream()` instead of the data member and so the data member is `null` in `writeToFile()` — IllegalArgumentException, Oct 06 '17 at 02:59

score 0 · Answer 1 · answered Oct 06 '17 at 03:02

As Johnny Mopp pointed out you have both an outFile in the createOutputStream method as well as an instance outFile. Try removing the File outFile = null; in the createOutputStream method then in the try, write:

this.outFile = new File("Nutrition.txt");
this.outFile.createNewFile();

I keep getting 'Exception in thread "main" java.lang.NullPointerException'

1 Answers1