address issue #1119 (serialization with protected/private constructor)

[stephengold]

No description provided.

[Ali-RS]

Transferred @pspeed42 comment from the other thread (#1180 (comment))

As for the real changes, isn't it odd to set accessible to true for ALL of the constructors only to then also specifically set it for the retrieved constructor?

Unless I'm missing something:
noArgConstructor.setAccessible(true);

...was enough. And:
AccessibleObject.setAccessible(allConstructors, true);

...is unnecessary.

[stephengold]

@pspeed42 is correct; that 2nd setAccessible() wasn't necessary. Thank you. I'll remove it.

[pspeed42]

Well, I mean setAccessible() on the constructor you will actually use might be better than calling it on every constructor in the whole class. It also means the find constructor method is doing what it says and not extra stuff.
Edit: Ah "Second setAccessible"... I may have read that wrong.

[Murph9]

Like the new InstantiationException

[pspeed42]

Much better.