a.java

bool isValidOffset(int x,int y,int width,int height){
    if(x < 0 || x > width) return false;
    if(y < 0 || y > width) return false;
    return true;
}

bitmap.cpp

for(int i=0;i<info.height;i++)
		for(int j=0;j<=info.width;j++)
		{
			if(j==info.width) //pad
			{
				int padding = 4 - ((info.width * 3) % 4);
				if(padding == 4)
					padding = 0;
				for(int k=0;k<padding;k++)
					file.read((char*)&temp_pad,sizeof(u_int8));
			}else
				file.read((char*)&datamap[i][j],sizeof(RGB));
		}

code.java

for (int i = 0; i < height; i++) {             
    int nullbytes = 4 -(width % 4);
    if(nullbytes == 4) {
        nullbytes = 0;
    }
    
    int splitWidth = Math.round((double)width / 8);
    for (int j = 0; j < splitWidth; j++) {
        if(j == splitWidth){
            byteStream.skipBytes(nullbytes);
        }else{
            byte b = byteStream.readByte();
            for(int k = 0; k <= 8;k++){
	      if((j+k)*8 <= width){
		System.out.println("I:= %d J:= %d",i,j*k);
		PixelArray[i][j+k] = (b & (byte)Math.pow(k,2)) == 1;
	      }
            }
        }
    }
}

BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);

for(int i=0;i<WIDTH;i++){
    for(int j=0;j<HEIGHT;j++){
        if(PixelArray[i][j]) image.setRGB(i, j, Color.BLACK.getRGB());
        if(!PixelArray[i][j]) image.setRGB(i, j, Color.WHITE.getRGB());
    }
}

ImageIO.write(image, "png", new File("C:\\out.png"));

pseudocode

from 0 to height:
  from 0 to width:
    if we are at the end of the row:
      calculate padding and skip it
    else:
      read the value