Java Scoping Error

Question

I was trying to write a mapper class for a practice program and the compiler always gives me error that: satMath and satVerbal might not have been initialized.

public class UniversityMapper  extends Mapper <LongWritable,Text,Text,IntWritable> {
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
  // TODO convert record (value) to String
    StringTokenizer iterator = new StringTokenizer (value.toString(),")" );
    int state = 2;
    int satVerbal;
    int satMath;

    while(state != 0 && iterator.hasMoreTokens())
    {
            String cur = iterator.nextToken();
            if (cur.contains("sat verbal"))
            {
                    state--;
                    StringTokenizer temp = new StringTokenizer(cur,"\\s+");
                    temp.nextToken();
                    temp.nextToken();
                    int satV = (new Integer(temp.nextToken())).intValue();
                    satVerbal = satV;
                    //context.write(new Text("satv"), new IntWritable(satVerbal));
            }

            else if (cur.contains("sat math"))
            {
                    state--;
                    StringTokenizer temp = new StringTokenizer(cur,"\\s+");
                    temp.nextToken();
                    temp.nextToken();
                    int satM = (new Integer(temp.nextToken())).intValue();
                    satMath = satM;
                    //context.write(new Text("satm"), new IntWritable(satMath));
            }


    }

    if (state == 0)
    {
            System.out.println(satVerbal);
            System.out.println(satMath);
            context.write(new Text ("satv"), new IntWritable(satVerbal));
            context.write(new Text ("satm"), new IntWritable(satMath));
    }
} }

If I reposition the context.write() method within the scope of the if statements (commented out in the code) I no longer get this error. I cannot understand why. I usually code in c++ and python I am really new to Java and I need to finish this program. Can somebody help me with this, thanks in advance :)

Answer 1

This is fairly straightforward. If this else if does't execute:

else if (cur.contains("sat math"))

Then you never initialize satMath, and you try to access it later via:

context.write(new Text ("satm"), new IntWritable(satMath));

Same goes with if (cur.contains("sat verbal")) and satVerbal.

If you wish to avoid these altogether you could just initialize + declare those variables yourself:

int satVerbal = 0;
int satMath = 0;

But you should be absolutely certain that they will be assigned something else inside your while, otherwise you will actually use their initialized values (0) later in your context.write, which I assume isn't desirable for you.