ok grazie... Gli errori nello specifico sono :

C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:1: cannot resolve symbol
symbol : class Scanner
location: package util
import java.util.Scanner;
^
C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:5: cannot resolve symbol
symbol : class Scanner
location: class Circonferenza
Scanner tastiera = new Scanner(in);
^
C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:5: cannot resolve symbol
symbol : class Scanner
location: class Circonferenza
Scanner tastiera = new Scanner(in);
^
C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:5: cannot resolve symbol
symbol : variable in
location: class Circonferenza
Scanner tastiera = new Scanner(in);
^
C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:8: operator * cannot be applied to java.lang.Double,int
diametro= (r * 2);
^
C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:9: operator * cannot be applied to java.lang.Double,double
circ = (diametro * 3.14);
^
C:\Documents and Settings\gianni\Desktop\Gianni\Java\Circonferenza\ Circonferenza.java:10: cannot resolve symbol
symbol : variable out
location: class Circonferenza
out.println("circonferenza=" + circ);
^
7 errors

Tool completed with exit code 1