Exception in thread "main" java.lang.NullPointerException.

[arrkaa]

hello all

Today I wrote a simple java program but it's error will make me crazy!
the program got this error:
Exception in thread "main" java.lang.NullPointerException.

there is only two class in my program (Triple and parse).
I have an array of the first class type in the second class.(static Triple[][] sentencesTriples= new Triple[...][...]

when I try to call a function of the first class in the second class, it got the mentioned error message.
(sentencesTriples[currentRow][currentColumn++].set(tokens[0], tokens[1], tokens[3])

do you have any idea to solve this problem?

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.util.StringTokenizer;
import java.util.regex.Pattern;
import java.util.regex.Matcher;



public class parse{




static int currentRow=0;
static int currentColumn=0;
static int numOfSentences=50;
static int maxNumOfRelations=40;


static Triple[][] sentencesTriples= new Triple[numOfSentences][maxNumOfRelations];

@SuppressWarnings("null")
public static void main(String[] args){

currentRow=0;
currentColumn=0;

try {

File fileSourceDependency = new File("C:/Users/green/Documents/NetBeansProjects/parsDependency/collapsed dependency for suppose in M_Tr.txt");

File outFile = new File("C:/Users/green/Documents/NetBeansProjects/parsDependency/matchSentences.txt");
BufferedReader inDependency = new BufferedReader(
new InputStreamReader(
new FileInputStream(fileSourceDependency), "UTF8"));

String strEn;

try {
Writer out_dependency_match = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outFile), "UTF8"));
while ((strEn = inDependency.readLine()) != null ) {

if(strEn.isEmpty()){
currentRow++;
currentColumn=0;

strEn=inDependency.readLine();
}


String[] tokens=new String[5];
for(int i=0; i<5;i++) tokens[i]=null;

StringTokenizer st;
st = new StringTokenizer(strEn," ");


for(int i=0;i<5;i++) tokens[i]=st.nextToken();

System.out.print(currentRow+" "+currentColumn+" "+tokens[0]+ tokens[1]+ tokens[3]+" ");

sentencesTriples[currentRow][currentColumn++].set(tokens[0], tokens[1], tokens[3]);


}


}
catch (IOException e)
{
System.out.println(e.getMessage());
}
}
catch (IOException e)
{
System.out.println(e.getMessage());
}

for (int i=0;i<20;i++)
for(int j=0;j< 5;j++){
System.out.println(sentencesTriples[i][j].getRelation()+" "+sentencesTriples[i][j].getArg1()
+" "+sentencesTriples[i][j].getArg2());
}
System.out.println("**End**");
}

}

[GregBrannon]

The array sentenceTriples is filled with nulls until you initialize each element:

sentenceTriples[i][j] = new Triple();

[arrkaa]

Thank you GregBrannon.
I am thinking why I didn't ask my question sooner!

Thank you again.

[GregBrannon]

You're welcome.