StringBuilder sb = new StringBuilder();

sb.append("Your area is: ");
sb.append(area);

if( sb.length() > 0 )
{
    System.out.println(sb.toString());
    sb.delete(0,sb.length());
}

sb.append("Your volume is: ");
sb.append(volume);

if(sb.length() > 0)
{
    System.out.println(sb.toString());
    sb.delete(0,sb.length());
}