It is reasonable to expect the same exceptions to be thrown for null; however, these api’s are very old and may not be able to be changed at this point.
And:
Since the exception behavior is long-standing and specified in the JavaDoc, it is impractical to change either method’s behavior at this time. Closing as will not fix.
As taken from: Bug Report: Integer.parseInt() and Double.parseDouble() throw different exceptions on null.
Like others have stated: It’s likely made by different authors.