Question

Hi im getting a Exception in thread "main" java.lang.NullPointerException. What is wrong?

Here is my code.

class MicrosoftMonarchs

{

//declaring all the arrays

public String array[];

public double close[];

public int volume[];

public double open[];

public double high[];

public double low[];

//declaring both size and totalFileData

public long totalFileData=0;

public int size=5;

//main file

public static void main(String[] args)

{

MicrosoftMonarchs data = new MicrosoftMonarchs();

//setting all the arrays equal to the size of the given text

data.array= new String[data.size];

data.close= new double[data.size];

data.volume= new int[data.size];

data.open= new double[data.size];

data.high= new double[data.size];

data.low= new double[data.size];

//read in the text file

data.readTextFile(data);

//print the data from the text file

data.printData(data);

//analyze the data from the text file

data.analyzeData(data);

}

//implementation of the read in from text file

public void readTextFile(MicrosoftMonarchs objdata)

{

//create data member i and set it to zero

int i=0;

BufferedReader reader;

//a try and catch block

try

{

//reading in the text file

reader = new BufferedReader(new FileReader("MicrosoftStockData.txt"));

String first=reader.readLine();

//while loop

while(first!=null)

{

//reading in the first line with commas in between each piece of data

first=reader.readLine();

String[] datas=first.split(",");

//assigning the data to the appropriate array

if(datas.length>0&&i<objdata.size)

{

objdata.array[i]=datas[0];

objdata.close[i]=Double.parseDouble(datas[1]);

objdata.volume[i]=Integer.parseInt(datas[2]);

objdata.open[i]=Double.parseDouble(datas[3]);

objdata.high[i]=Double.parseDouble(datas[4]);

objdata.low[i]=Double.parseDouble(datas[5]);

}

i++;

objdata.totalFileData++;

}

//stop reading in once there is nothing left from the text file

reader.close();

}

//generic catch block

catch(IOException e)

{

e.printStackTrace();

}

}

//implementation of the printData class

public void printData(MicrosoftMonarchs objdata)

{

//create data member i and set it to zero

int i=0;

//Printing out the data

System.out.println(objdata.totalFileData+"data lines read from 'MicrosoftStockData.txt'");

System.out.println("First 12 days of data ranging from " + objdata.array[0]+"-" +objdata.array[3]);

System.out.println("Date"+" "+"Close"+ " "+"Volume"+" "+"Open"+" "+"High"+" "+"Low/n");

//a for loop which prints out the data four times

for(i=0; i<4; i++)

{

System.out.print(objdata.array[i]+" "+objdata.close[i]+" "+objdata.volume[i]+" "+objdata.open[i]+" "+objdata.high[i]+" "+objdata.low[i]+"/n");

}

}

//implementation of the analyzeData class

public void analyzeData(MicrosoftMonarchs objdata)

{

//declare two variables for both high and low

double highData=objdata.close[0];

double lowData=objdata.close[0];

//declare the indexes

int indexA=0;

int indexB=0;

//

for(int i=1; i<objdata.close.length; i++)

{

if(objdata.close[i]> highData)

{

highData=objdata.close[i];

indexB=i;

}

if(objdata.close[i]< lowData)

{

lowData=objdata.close[i];

indexA=i;

}

}

System.out.println("Highest closing stock data date: "+objdata.array[indexB]+" and volume: "+objdata.volume[indexB]);

System.out.println("Lowest closing stock data date: "+objdata.array[indexA]+" and volume"+objdata.volume[indexA]);

double highDiff=objdata.high[0]-objdata.low[0];

indexB=0;

for(int i=1; i<objdata.close.length; i++)

{

if((objdata.high[i]-objdata.low[i])>highDiff)

{

highDiff=objdata.high[i]-objdata.low[i];

indexB=i;

}

}

System.out.println("Highest diffrence data: "+objdata.array[indexB]+" and value: "+highDiff);

}

}

Answer 1

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

class MicrosoftMonarchs
{
    //declaring all the arrays
    public String array[];
    public double close[];
    public int volume[];
    public double open[];
    public double high[];
    public double low[];
    //declaring both size and totalFileData
    public long totalFileData=0;
    public int size=5;

    //main file
    public static void main(String[] args)
    {
        MicrosoftMonarchs data = new MicrosoftMonarchs();
//setting all the arrays equal to the size of the given text
        data.array= new String[data.size];
        data.close= new double[data.size];
        data.volume= new int[data.size];
        data.open= new double[data.size];
        data.high= new double[data.size];
        data.low= new double[data.size];
//read in the text file
        data.readTextFile(data);
//print the data from the text file
        data.printData(data);
//analyze the data from the text file
        data.analyzeData(data);
    }
    //implementation of the read in from text file
    public void readTextFile(MicrosoftMonarchs objdata)
    {
//create data member i and set it to zero
        int i=0;
        BufferedReader reader;
//a try and catch block
        try
        {
//reading in the text file
            reader = new BufferedReader(new FileReader("MicrosoftStockData.txt"));
            String first=reader.readLine();
//while loop
            while((first=reader.readLine()) != null)    // read first then check if it is null
            {
//reading in the first line with commas in between each piece of data
                String[] datas=first.split(",");
//assigning the data to the appropriate array
                if(datas.length>0&&i<objdata.size)
                {
                    objdata.array[i]=datas[0];
                    objdata.close[i]=Double.parseDouble(datas[1]);
                    objdata.volume[i]=Integer.parseInt(datas[2]);
                    objdata.open[i]=Double.parseDouble(datas[3]);
                    objdata.high[i]=Double.parseDouble(datas[4]);
                    objdata.low[i]=Double.parseDouble(datas[5]);
                }
                i++;
                objdata.totalFileData++;
            }
//stop reading in once there is nothing left from the text file
            reader.close();
        }
//generic catch block
        catch(IOException e)
        {
            e.printStackTrace();
        }
    }
    //implementation of the printData class
    public void printData(MicrosoftMonarchs objdata)
    {
//create data member i and set it to zero
        int i=0;
//Printing out the data 
        System.out.println(objdata.totalFileData+"data lines read from 'MicrosoftStockData.txt'");
        System.out.println("First 12 days of data ranging from " + objdata.array[0]+"-" +objdata.array[3]);
        System.out.println("Date"+" "+"Close"+ " "+"Volume"+" "+"Open"+" "+"High"+" "+"Low/n");
//a for loop which prints out the data four times
        for(i=0; i<4; i++)
        {
            System.out.print(objdata.array[i]+" "+objdata.close[i]+" "+objdata.volume[i]+" "+objdata.open[i]+" "+objdata.high[i]+" "+objdata.low[i]+"/n");
        }
    }
    //implementation of the analyzeData class
    public void analyzeData(MicrosoftMonarchs objdata)
    {
//declare two variables for both high and low
        double highData=objdata.close[0];
        double lowData=objdata.close[0];
//declare the indexes
        int indexA=0;
        int indexB=0;
//
        for(int i=1; i<objdata.close.length; i++)
        {
            if(objdata.close[i]> highData)
            {
                highData=objdata.close[i];
                indexB=i;
            }
            if(objdata.close[i]< lowData)
            {
                lowData=objdata.close[i];
                indexA=i;
            }
        }
        System.out.println("Highest closing stock data date: "+objdata.array[indexB]+" and volume: "+objdata.volume[indexB]);
        System.out.println("Lowest closing stock data date: "+objdata.array[indexA]+" and volume"+objdata.volume[indexA]);
        double highDiff=objdata.high[0]-objdata.low[0];
        indexB=0;
        for(int i=1; i<objdata.close.length; i++)
        {
            if((objdata.high[i]-objdata.low[i])>highDiff)
            {
                highDiff=objdata.high[i]-objdata.low[i];
                indexB=i;
            }
        }
        System.out.println("Highest diffrence data: "+objdata.array[indexB]+" and value: "+highDiff);
    }
}