Fields and methods should always be imported by their canonical name. The canonical name of a top-level class is the fully-qualified name of the package, followed by a ., followed by the name of the class. The canonical name of a member class is the canonical name of its declaring class, followed by a ., followed by the name of the member class. The canonical name of a field or method is the canonical name of the type it is declared in, followed by a ., followed by the name of the field or method.

Fully-qualified names are not necessarily canonical. Consider some field f declared in a class C. There may be another class D that extends C and inherits f. Therefore f can be accessed using the fully-qualified name D.f. Since f is not declared in D, this name is not canonical.

The JLS §7.5.3 requires all single static imports to start with a canonical type name, but the fully-qualified name of the imported member is not required to be canonical.

Importing members using non-canonical names is unnecessary and unclear, and should be avoided.

Example:

package a;

class One {
  public static final int CONST = 42;
}

package a;

class Two extends One {}

An import of CONST should always refer to it using the canonical name a.One.CONST, not a.Two.CONST.