关于Java浮点运算精确的问题

Question

早知道在java中，浮点运算会出现不精确的情况。解决方案是BigDecimal类。
今天发现个问题：

System.out.println(2-1.1);//0.8999999999999999

System.out.println(2.0-0.9);//1.1

只要没有整数位的都会出现问题？
Why？

Answer 1

The reason is that floating point numbers are composed of two parts: exponent and mantissa. After floating point numbers are converted into binary and participate in calculations, the conversion process will become unpredictable and irreversible
The second situation you mentioned It just happened that no accuracy loss was noticed during the conversion process

Answer 2

This problem is not limited to Java, other languages ​​may also have this problem.