Java Eclipse：类无法解析为类型继承

Question

I've run into an issue where when I open projects in Eclipse there is something wrong with the visibility of classes across packages.

Example:

package.a
   - public abstract class clazz
package.b
   - public abstract class clazzy extends clazz

In the above instance clazzy would have an error, where clazz wouldn't available. If I move clazzy into package.a, and the move it back to package.b everything is fine, but otherwise I can't get eclipse to recognize that clazz exists at all.

EDIT 1:

Yes, I am importing the class. I also press ctrl-shift-o (import). If I hand type out the import, eclipse still fails to recognize that clazz exists. I have not tried importing the entire package, as generally I avoid doing this for a whole variety of reasons.

Edit 2:

When I first open the project (it can already exist in the workspace) with the following imports:

import package.a.Clazz;

public abstract clazzy extends Clazz {
...
}

Both the import, and the clazz identifier will be underlined in red.

I have received several suggestions to do:

import package.a;

Which not only does not resolve the issue, but I also would not want to do for a variety pf reasons.

Edit 3:

I should clarify that when I say "move" in the 2nd paragraph, i mean that if I move package.b.clazzy into another package (say package.a, or package.c) eclipse seems to realize it's being stupid and sorts itself out. If I then move clazzy back into package.b everything is fine from that point on.

This code compiles and runs correctly from that point on.

Answer 1

I solved that with adding this import:

import javax.persistence.InheritanceType;

hope it may help someone :)

Answer 2

Your problem might be a naming issue... package is a keyword in Java and should not be used for names of a package, variable, class etc.

Rename your package to a . For that you either recreate it or move the content in a new directory named a and change the package identifier at the top of the class to package a .

Answer 3

import the package like this

import a.clazz;

not as package is th reserved keyword in java

import package.a.clazz;

add the import in your code to inherit the class

Answer 4

If you don't want to import package.a.clazz (why not?) then you need to refer to it via its full name,

public abstract class clazzy extends package.a.clazz {

But I really don't know why you would want to do that instead of

import package.a.clazz;

public abstract class clazzy extends clazz {

In fact, the reason why the "move" in Eclipse works is because Eclipse, when it moves clazzy to the new package, automatically adds the import statement for you.

Also, be careful to use the right case. In your question, you used all lower case, but in your edits, you started referring to Clazz not clazz . Those are different, where only the first ( Clazz ) follows standard conventions.