Minesweeper game in java

minesweeper Program in java

Minesweeper.java

import java.util.Random;
public class Minesweeper {
  int _row=5,_col=5,_countGameOver=0;
  int [][] _board=new int[_row][_col];
  boolean [][] _flagMatrix=new boolean[_row][_col];
 public void plotBoard(){
 int noOfBomb=_col;
while(noOfBomb>0) {
 int i=getRandomNumber();
 int j=getRandomNumber();
 if (_board[i][j]!=-1) {
_board[i][j]=-1;
noOfBomb--;
  }
 }
  }
public int getRandomNumber(){
Random t = new Random();
// random integers in [0, 100]
int num;
{
num=t.nextInt(_col);
}while(num>_col);
return num;
    }
boolean isValid(int i,int j){
return((i>=0 && i<_row)&&(j>=0 && j<_col));
}
int getAdjBomb(int i,int j){
int num=0;
//System.out.println("i="+i+"j="+j);
for (int k = i-1; k <=(i+1); k++) {
for (int l= j-1; l<=(j+1); l++) {
    if (isValid(k,l)&&(_board[k][l]==-1)) {
num++;
   }
    }
}
return num;
}
public void calculateCounts(){
for (int i = 0; i <_row; i++) {
    for (int j = 0; j <_col; j++) {
    if(_board[i][j]!=-1)
       _board[i][j]=getAdjBomb(i,j);
    }
}
}
public void print(){
for (int i = 0; i <_row; i++) {
for (int j = 0; j <_col; j++) {
System.out.print(" "+_board[i][j]);
}
System.out.println("");
}
}
public void displayFlagMatrix(){
for (int i = 0; i <_row; i++) {
   for (int j = 0; j <_col; j++) {
    if (_flagMatrix[i][j]==true) {
    System.out.print(" "+"*");
}
    else{
    System.out.print(" "+"+");
    }
   }
System.out.println(" ");
}
}
public boolean play(int r,int c){
if (!(isValid(r,c))) {
System.out.println("Please Enter row and col in correct range");
return false;
}
if (_flagMatrix[r][c]==true) {
System.out.println("This is a open position please enter other col and row");
return false;
}
if (_board[r][c]==-1)
return true;
if (_board[r][c]!=0) {
_countGameOver++;
_flagMatrix[r][c]=true;
}
else{
_flagMatrix[r][c]=true;
_countGameOver++;
openSpace(r, c);
}
return false;
}
void openSpace(int r,int c){
for (int k = r-1; k <=(r+1); k++) {
   for (int l= c-1; l<=(c+1); l++) {
            if (isValid(k,l)&&(_board[k][l]!=-1)&&(_flagMatrix[k][l]==false)) {
             _flagMatrix[k][l]=true;
              _countGameOver++;
          if (_board[k][l]==0) {
             openSpace(k,l);
          }
         }  
    }
}
}
public boolean checkGameOver(){
return(_countGameOver==(_row*_row)-(_row));
}
}

++++++++++++++++++

MainMinessweeper.java

import java.util.Scanner;
import com.jan21.*;
public class MainMinesweeper extends Minesweeper {
public static void main(String[] args) {
MainMinesweeper obj=new MainMinesweeper();
    obj.plotBoard();
    obj.calculateCounts();
    System.out.println("afate count");
    obj.print();
    int r,c;
    System.out.println("+++++++++++++++");
    obj.displayFlagMatrix();
    while(true){
  System.out.println("===============");
    Scanner input=new Scanner(System.in);
    System.out.println("enter row");
    r=input.nextInt();
    System.out.println("enter col");
    c=input.nextInt();
    if (obj.play(r,c)) {
System.out.println("You Lose");
break;
  }
System.out.println("ok");
if (obj.checkGameOver()) {
obj.displayFlagMatrix();
System.out.println("You Win Game");
break;
}
obj.displayFlagMatrix();
System.out.println("+++++++++++");
obj.print();

  }
}

}