Java newbie. some error

Question

hi! this is my code. i am getting the error given in the end. can any one help.
(i have just written the matrix multiplicartion. dont know if it works.)
class Mult
     private int arr1[][] ={{1,2,3},{2,3,4},{4,5,6}};
     private int arr2[][] ={{1,2,3},{2,3,4},{4,5,6}};
     public static void main(String[] args)
          System.out.println("Hello World!");
               Matrix m = new Matrix();          
          m.PrintMatrix(arr1);
class Matrix
     int Mat [][]=new int[3][3];
     int tmp=0;
     void Multiply(int arr1[][],int arr2[][])
          for (int k=0;k<3 ;k++ )
               for(int i=0;i<3;i++)
                    for (int j=0;j<3 ;j++ )
                              tmp+=arr1[i][k]*arr2[k][j];
                    Mat[i][k]=tmp;
                    tmp=0;
     void PrintMatrix(int arr[][])
          System.out.println("");
          for (int i=0;i<3 ;i++ )
               for(int j=0;j<3;j++)
                    System.out.print(arr[i][j]+ " ");
               System.out.println("");
Mult.java:11: non-static variable arr1 cannot be referenced from a static contex
t
m.PrintMatrix(arr1);
^
1 error
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Answer 1

main() is a static method. Therefore it has no access to instance variables because it has no this pointer. To fix it you need to either instantiate a new Mult object and put your runtime code there or make your arrays static.