Refactor : remove superfluous exceptions in throws declaration

[JooHyukKim]

Summary

• Both StreamReadException and DatabindException are subclass of IOException so the former two are not required
• Plus From what I understood in issue #1675, we are moving away from checked exceptions by wrapping IOException with JsonProcessingException. So this might prevent confusion in the future??

[pjfanning]

-1 from me - still an API change under any definition of an API change - there is absolutely no harm in having the 3 classes declared

The master branch is for the future v3 release and the exceptions are being refactored there. No point in changing anything on v2 branches.

[JooHyukKim]

The master branch is for the future v3 release and the exceptions are being refactored there. No point in changing anything on v2 branches.

Ah, I see. Then it makes even less sense for this PR to be commited.

[JooHyukKim]

CLOSED

Will close this Issue quoting from @pjfanning that

The master branch is for the future v3 release and the exceptions are being refactored there. No point in changing anything on v2 branches.

[cowtowncoder]

You are of course right @JooHyukKim that it is redundant, non-minimal.

But to me this is one of those cases where I think more verbose method declarations are good for documentation purposes; javadocs referencing separate subtypes.

But as @pjfanning pointed out, yes, we are moving to unchecked exceptions in 3.0 (master), and will only declare base JacksonException (or, in some cases, nothing, it being optional as well).