📅  最后修改于: 2022-03-11 14:52:25.485000             🧑  作者: Mango
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public class Test {
public static void main(String[] s) {
Map whoLetDogsOut = new ConcurrentHashMap<>();
whoLetDogsOut.computeIfAbsent("snoop", k -> f(k));
whoLetDogsOut.computeIfAbsent("snoop", k -> f(k));
}
static boolean f(String s) {
System.out.println("creating a value for \""+s+'"');
return s.isEmpty();
}
}