Why do Double.parseDouble(null) and Integer.parseInt(null) throw different exceptions?
Is this a historical accident or intentional? The documentation clearly states two types of exceptions for Double.parseDouble(...) and one for Integer.parseInt(), but it seems inconsistent:
Integer.parseInt(null); // throws java.lang.NumberFormatException: null
However
Double.parseDouble(null); // throws java.lang.NullPointerException
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.
Note: everything in this post is in the source of Java7-b147
Double.parseDouble() goes into a Sun library (in sun.misc.FloatingDecimal) the first important thing that happens is:
in = in.trim(); // don't fool around with white space.
// throws NullPointerException if null
Integer.parseInt() is done manually in the Integer class. The first important thing that happens is:
if (s == null) {
throw new NumberFormatException("null");
}
I would guess there are two different authors.
doubleprimitive docs.oracle.com/javase/tutorial/java/nutsandbolts/…parseDoubledoes not do a null check, and just throws an NPE when it is encountered, but inparseInt, then input string is checked fornull. I can't see any good reason why they should behave different.