Can anyone plz help me how to find correlation matrix for more than 3 attributes in java

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Java

I have a dataset in .xlsx(excel) format which has 8 attributes..and there are many missing values in those attributes..so the task i need to do is to replace the missing values by using expectation maximization algorithm.
so the basic step in expectation maximization is finding its correlation matrix..
the following code is to find correlation only between two attributes.
but i want to find correlation among all 8 attributes by giving a file as input
can any one plz link the code for this..?

import java.util.*;
import java.lang.*;
class Correlation_coefficient
{
public static void main(String args[])
{
double r,nr=0,dr_1=0,dr_2=0,dr_3=0,dr=0;
double xx[],xy[],yy[];
xx =new double[5];
xy =new double[5];
yy =new double[5];
double x[]={60,61,62,63,65},y[]={3.1,3.6,3.8,4.0,4.1};
double sum_y=0,sum_yy=0,sum_xy=0,sum_x=0,sum_xx=0;
int i,n=5;
for(i=0;i<n;i++)
{
xx[i]=x[i]*x[i];
yy[i]=y[i]*y[i];
}
for(i=0;i<n;i++)
{
sum_x+=x[i];
sum_y+=y[i];
sum_xx+= xx[i];
sum_yy+=yy[i];
sum_xy+= x[i]*y[i];
}
nr=(n*sum_xy)-(sum_x*sum_y);
double sum_x2=sum_x*sum_x;
double sum_y2=sum_y*sum_y;
dr_1=(n*sum_xx)-sum_x2;
dr_2=(n*sum_yy)-sum_y2;
dr_3=dr_1*dr_2;
dr=Math.sqrt(dr_3);
r=(nr/dr);
String s = String.format("%.2f",r);
r = Double.parseDouble(s);
System.out.println("Total Numbers:"+n+"\nCorrelation Coefficient:"+r);
}
}