Importing Java packages and classes

Can this be always generalised and be said that in the import statement, the first one would be java/javax (is there any other?), the second one package, the third class and the fourth, if any will always be a method belonging to the class?

Not really, no.

The package is java.util, and you'll definitely see other packages, including the ones you write.

Within a normal import statement, there'll be a package, then either a specific class name or a * (to import all the classes in a package). But the class name could be a nested class name, so you could have:

import foo.bar.Outer.Nested;

where foo.bar is the package name, and Outer.Nested is the class name.

Then there are static imports, where you import members of classes, e.g.

import static java.lang.Math.sqrt;

See the Java tutorial on imports for more details.