Tuesday, January 23, 2007

Star imports

When pepole asked me why star imports are bad, I didn't really know what to answer. Usually I was talking about parsing time and so.
And actually IDEs like Eclipse or IntelliJ even offer to reorganize individual imports into star imports (I think IntelliJ does this as default).

Today I was doing a bigger refactoring and was moving packages around.
Eclipse is doing a really good job here.

Unfortunately I was getting compile errors afterwards, because the old packages did no longer exist.
The reason behind this is that a refactoring is a textual replacement and not a semantical. Example:

import foo.*;

public class Bar {
Foo f;

Now you move foo.Foo to baz.Foo. Eclipse adds the new import baz.Foo statement, but does not remove
foo.*, as is does basically not know that foo.* no longer exists (it could analyze all statements in the class and
automatically remove unused imports afterwards though).

1 comment:

Jety said...

Thanks, this helped me to realise, why star imports are bad (doing code review now).