java - 关系运算符在哪些方面不遵守浮点值的 compareTo 契约？

Question

引自 Effective Java - Second Edition by Joshua Bloch

For floating-point fields, use Double.compare or Float.compare in place of the relational operators, which do not obey the general contract for compareTo when applied to floating point values.

它没有详细说明为什么会这样。

那么，我的问题是:

当与浮点值一起使用时，关系运算符在哪些方面不遵守 compareTo 的一般约定？

Answer 1

来自javadoc :

 public int compareTo(Double anotherDouble)

Compares two Double objects numerically. There are two ways in which comparisons performed by this method differ from those performed by the Java language numerical comparison operators (<, <=, ==, >=, >) when applied to primitive double values: Double.NaN is considered by this method to be equal to itself and greater than all other double values (including Double.POSITIVE_INFINITY). 0.0d is considered by this method to be greater than -0.0d. This ensures that the natural ordering of Double objects imposed by this method is consistent with equals.