我需要它的一次(也是唯一一次)是与IBM ZSeries进行协调。在会计和大型机之外;不。有一段时间了，但我相当确定大型机没有改变。

一切都始于一个故事，

When java was being developed by James Gosling, Herbert and rest of his team. They had this crazy thing in mind called platform independency. They wanted to make oak(Java) so much better that it would run exactly same on any machine having different instruction set, even running different operating systems. But, there was a problem with decimal point numbers also known as floating point and double in programming languages. Some machines were built targeting efficiency while rest were targeting accuracy. So, the later(more accurate) machines had size of floating point as 80 bits while the former(more efficient/faster) machines had 64 bit doubles. But, this was against there core idea of building a platform independent language. Also, this might lead to loss of precision/data when a code is built on some machine(having double of 64 bit size) and run on another kind of machine(having double of 80 bit size).

扩大规模是可以容忍的，但缩小规模是不能容忍的。 因此，他们遇到了strictfp的概念，即严格浮点数。如果在类/函数中使用此关键字，则其浮点数和双精度浮点数在任何机器上都具有一致的大小。即分别为32位/64位。

Strictfp确保在每个平台上从浮点计算中得到完全相同的结果。如果不使用strictfp, JVM实现可以在可用的地方使用额外的精度。

来自JLS:

Within an FP-strict expression, all intermediate values must be elements of the float value set or the double value set, implying that the results of all FP-strict expressions must be those predicted by IEEE 754 arithmetic on operands represented using single and double formats. Within an expression that is not FP-strict, some leeway is granted for an implementation to use an extended exponent range to represent intermediate results; the net effect, roughly speaking, is that a calculation might produce "the correct answer" in situations where exclusive use of the float value set or double value set might result in overflow or underflow.

换句话说，就是要确保Write-Once-Run-Anywhere实际上意味着write - once - get - equal - wrong - results - everywhere。

使用strictfp，您的结果是可移植的，没有它，它们更可能是准确的。

'strictfp'关键字用于强制Java中的浮点计算(float或double)的精度显式符合IEEE的754标准。如果不使用strictfp关键字，浮点精度取决于目标平台的硬件。

如果接口或类使用strictfp声明，那么该接口或类中的所有方法和嵌套类型都是隐式strictfp。

参考链接

strictfp is a modifier which restricts floating point calculations as per IEEE 754. This can be used on whole class like "public strictfp class StrictFpModifierExample{}" or on method "public strictfp void example()".If it is used on class than all methods will follow IEEE 754 and if used on method then particular method will follow IEEE 754. Why it is used??::: As different platforms have different floating point hardware which calculates with more precision and greater range of values than the java specification requires which may produce diffrent output on diffrent plateforms.so it confirms the same output irrespective of diffrent plateforms strictfp also ensures to take advantage of the speed and precision of the extended precision floating-point operations. There is no disadvantage with this keyword we can use when we are doing floating point calculations My last point is --What is IEEE754 in short IEEE 754 defines standard method for both floating point calculations and storage of floating point values in either single (32-bit, used in Java floats) or double (64-bit, used in Java doubles) precision.It also defines norms for intermediate calculations and for extended precision formats.

也许下面的例子有助于更清楚地理解这一点: 在java中，当我们使用查找任何操作的精确信息时，例如。 如果我们做double num1 = 10e+102;Double num2 = 8e+10; 结果= num1+ num2;

        The output will be so long and not precise, becasue it is precissed by the hardware e.g JVM and JIT has the license 
        as long as we dont have specify it Strictfp

Marking it Strictfp will make the result Uniform on every hardware and platform, because its precised value will be same
One scenario I can see is in a distributed application (or multiplayer game) where all floating-point calculations need to 
be deterministic no matter what the underlying hardware or CPU is.