java - Double 类中 NaN、POSITIVE_INFINITY 和其他一些常量的值设置是多少？

Question

NaN、POSITIVE_INFINITY 和 Double 类中的一些其他常量的值是多少？从源代码中，我看到它们设置为自己，但这是如何工作的？

public final class Double extends Number implements Comparable<Double> {
    public static final double POSITIVE_INFINITY = POSITIVE_INFINITY;
    public static final double NEGATIVE_INFINITY = NEGATIVE_INFINITY;
    public static final double NaN = NaN;
    public static final double MAX_VALUE = MAX_VALUE;
    public static final double MIN_VALUE = MIN_VALUE;

    ...
}

谢谢。

Answer 1

至少在 OpenJDK 8 , OpenJDK 9和 OpenJDK 10 ，它们在源代码中:

public static final double POSITIVE_INFINITY = 1.0 / 0.0;
public static final double NEGATIVE_INFINITY = -1.0 / 0.0;
public static final double NaN = 0.0d / 0.0;  // (*)
public static final double MAX_VALUE = 0x1.fffffffffffffP+1023;
public static final double MIN_VALUE = 0x0.0000000000001P-1022;

(*) In case you're wondering about the "d"...