On the small problem of the deviation of Java double multiplication

Take a look at the results of the following 1 piece of code:

public class TestDouble { 

public static void main(String[] args) { 

double d =538.8; 

System.out.println(d*100); 

}

The output was surprisingly not 53880 but 53879.99999999999

Solution 1:

538.8*100 and replace it with *10*10 to get what we want

538.8 times 10000 is replaced by 100 times 100.

Solution 2:

public class TestDouble { 
  public static void main(String[] args) { 
   double d =538.8;   
   BigDecimal a1 = new BigDecimal(Double.toString(d)); 
   BigDecimal b1 = new BigDecimal(Double.toString(100));  
   BigDecimal result = a1.multiply(b1);//  Multiply the result  
   System.out.println(result); 
   BigDecimal one = new BigDecimal("1"); 
   double a = result.divide(one,2,BigDecimal.ROUND_HALF_UP).doubleValue();// keep 1 digits  
   System.out.println(a); 
  } 
}