Thread: Something wrong with array

import java.io.*;
public class Prim {
	public static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
....
 
        public static tempEdge [] tedges;
....
 
        public Graph graph;
 
        private static int tempi = 0, one, two, size;
 
        public void buildTable(String file){
 
            n = 10;//menu.numOfNodes();
            tedges = new tempEdge[n*(n-1)/2];
            try{
                BufferedReader input = new BufferedReader(new FileReader(file));
                while(input.ready())
                {
                   String tmp = input.readLine();
                   String[] newPoint = tmp.split(" ");
                   int p1 = Integer.parseInt(newPoint[0]);
                   int p2 = Integer.parseInt(newPoint[1]);
                   int dis = Integer.parseInt(newPoint[2]);
                   tedges[tempi] = new tempEdge(p1,p2,dis);
                   System.out.println(tedges[tempi].firstPoint());
                   System.out.println(tedges[tempi].secondPoint());
                   System.out.println(tedges[tempi].distance());
                   tempi++;
                 }
            }
            catch(IOException e)
            {
		System.out.println("Error, file does not exist");
            }
            prims();
        }
        //create a minal spanning tree
	public static void prims()
	{
                n = 5;//menu.numOfNodes();
                //set size of the array which store different things
		Graph = new int[n+1][n+1];
		Tree = new int[n+1][3];
		near = new int[n+1];
 
                while(tedges != null){
                   for(int i=0;i<=tedges.length;i++){
                        //tempEdge e = tedges[i];
                            one = tedges[i].firstPoint();
                            System.out.println("1");
                            two = tedges[i].secondPoint();
                            size = tedges[i].distance();
                            if((one!=two)&&(one<two)) {
                                Graph[one][two] = Graph[two][one] = size;
                                if(Graph[one][two] == 0 )
                                    Graph[two][one] = Graph[one][two] = 7001;
                            }
                            if(one==two)
                                Graph[one][two]=7001;
                       }
                    }
 
		getMinKL();
		mincost = Graph[k][l];
		Tree[1][1] = l;
		Tree[1][2] = k;
		for(int i=1; i<=n; i++)
			near[i] = (Graph[i][l]<Graph[i][k])?l:k;
		near[k] = near[l] = 0;
 
		for(int i=2; i<n; i++)
		{
			int j = getMin();
			Tree[i][1] = j; Tree[i][2] = near[j];
			mincost = mincost+Graph[j][near[j]];
			near[j] =0;
			for (int k=1; k<=n; k++)
				if( (near[k] !=0) && Graph[k][ near[k] ]> Graph[k][j] )
					near[k] =j;
		}
                tri.createNode();
	}
.......
 
        public static void main (String[] args) throws IOException
        {
               Prim prim = new Prim();
               prim.buildTable("3Dtriangle.txt");
 
               System.out.println("Solution : ");
		for (int i = 1; i<=n; i++)
		{
			if( (Tree[i][1]!=0) && (Tree[i][2] !=0) )
				System.out.println(Tree[i][1] + "-" +Tree[i][2]);
                                System.out.println(Graph[Tree[i][1]][Tree[i][2]]);
		}
	}
}

I got a file with 6 line in it and
After i run the code, it shows
1
2
50
1
3
Exception in thread "main" java.lang.NullPointerException
60
1
4
70
2
3
80
2
4
40
3
4
60
1
1
1
1
1
1
at triangle_projection.Prim.prims(Prim.java:69)
at triangle_projection.Prim.buildTable(Prim.java:55)
at triangle_projection.Prim.main(Prim.java:178)

can anyone please help me to solve it?
Thank you

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