请帮小弟分析一下（八皇后）问题的错误（有分竟答）

我改了一些错误, 在jb上运行是对的.
//Queen.java
import javax.swing.*;
public class Queens
{
        int[] a = new int[8];
        int[] b = new int[15];
        int[] c = new int[15];
        int[][] Queen = new int[8][8];
        String output = "";
        void next( int i )
        {
             for( int j=0;j<8;j++ )
              {
                if( a[j]==0 && b[i+j]==0 && c[i-j+7]==0 )
                {
                     a[j] = b[i+j] = c[i-j+7] = 1;
                     Queen[i][j]=1;
                     if( i<7 )
                      next( i+1 );
                     else
                     {
                             String output = new String();
                             for( int m=0;m<8;m++ )
                              {
                                 for( int n=0;n<8;n++ )
                                         output+="      "+Queen[m][n]+"      ";
                                  output+="\n";     
                             }
                             JTextArea outputArea = new JTextArea();
                             outputArea.setText(output);
                             JOptionPane.showMessageDialog( null, outputArea, "Onepossible distribution", JOptionPane.INFORMATION_MESSAGE );
                      }
                      a[j] = b[i+j] = c[i-j+7] = Queen[i][j]=0;
                }
        } 
   }
   public static void main( String args[] )
   {
        Queens one = new Queens();
        one.next(0);
        System.exit(0);
   }
}