Re: what are "import" statements exactly ?
LC wrote:
Will a class file compiled with lots of wildcard import be bigger or less
efficient than one with a few specific import ?
Jeff Higgins <oohiggins@yahoo.com> wrote:
Andreas Leitgeb wrote:
Really: "No, but ..."
Really, no but, but "No." The question was about whether class files would be
bigger or slower, not compilations.
.... with a really large list of import-statements, compile-time will increase,
Compile time will increase to a degree not noticeable to the human time sense.
and what's worse: the general likeliness of the compiler
picking a "wrong" class will be higher. Equal class-names can occur
The likelihood of the compiler picking the right class is exactly the same
with imports-on-demand as with single-type imports, assuming you've included
all the right packages in both cases.
Best practice is to import exactly the classes needed using single-type imports.
in different packages. If two packages with some common class-names
are imported, then the compiler picks one, and that isn't necessarily
If you import two classes via single-type-imports that have the same
unqualified name, the compiler does not pick one.
If you import two packages via imports-on-demand that have a class with the
same name, and you try to use that unqualified name, the compiler does not
pick one.
the one *you* had in mind. This problem can even occur when a
certain java-source has no "import"-statement at all, but in the same
package there are other classes with names like classes from java.lang
since both that and the current package are implicitly imported.
Don't ever name a class the same as one in java.lang or javax.lang.
PS: Of course, "unexpectedness" often depends on the one not expecting :-)
"Unexpected" could mean that one didn't study the rules, and didn't know what
to expect. Expectations depend entirely and always on the one expecting.
People use the word to externalize their own decisions: "I wasn't expecting
that!" Not the fault of the event, don't'cha know.
--
Lew