java.lang.NullPointerException

[vasavi.singh]

Hi,

In my program I am trying to access the variable of other class. But it is giving NullPoinerException.

LinearThresholdModel.java

import jsns.model.CommunicationNetworkId;
import jsns.model.util.ContinuousTime;
import jsns.model.util.LoggingMasterImpl;
import jsns.model.IEnvironment;
import jsns.model.util.EnvironmentImpl;
import jsns.system.SimulationControl;
import java.lang.String;
import java.io.*;
import java.util.*;

public class LinearThresholdModel
{
SocialNetworkCons network=new SocialNetworkCons();
public void methodImplementation(int authorCount)
{
int j=0,activeNodes[]=new int[50];
System.out.println(network.networkIds);
System.out.println(network.networkIds[0].getNetworkId());
System.out.println("AuthorCount: "+authorCount);

for(int i=0;i<=authorCount;i++)
{
System.out.println("Method Implementation"); // till this point executes well
int degree=network.author[i].getDegree(); // raising exception
System.out.println("Degree: "+degree);
System.out.println("The count of active nodes in the network are "+j);
}
}

The above method "methodImplementation()" is called in Main.java

Main.java

import jsns.model.CommunicationNetworkId;
import jsns.model.util.ContinuousTime;
import jsns.model.util.LoggingMasterImpl;
import jsns.model.IEnvironment;
import jsns.model.util.EnvironmentImpl;
import jsns.system.SimulationControl;
import java.lang.String;
import java.io.*;
import java.util.*;

public class Main
{
public static void main(String args[]) throws IOException
{
StoreDataInAFile fileObj=new StoreDataInAFile();
SocialNetworkCons network=new SocialNetworkCons();
// fileObj.writeDataIntoAFile();
String data[]=fileObj.readDataFromAFile();
int authorsId[]=new int [20],temp=-1;
LinearThresholdModel model=new LinearThresholdModel();

System.out.println("Number of elements: "+data.length);
int authorCount=network.constructingSocialNetwork(data );
System.out.println("Author Count: "+authorCount);
model.methodImplementation(authorCount);
}
}

can u help me regarding this

[mtyoung]

are you sure SocialNetworkCons object "network" in two difference classes are the same?

[itsmegb]

int degree=network.author[i].getDegree(); // raising exception

It looks like maybe author has no contents. is it being initialised?

Without seeing the contents of SocialNetworkCons() its hard to be sure.

hope that helps!

p.s. please use the Code tags next time!

George