Which two methods from the java.util.stream.Streaminterface perform a reduction operation?
(Choose two.)

Given the code fragment:

Which is the valid definition of the Course enum?

Given the code fragment:
List<String> colors = Arrays.asList("red", "green", "yellow");
Predicate<String> test = n - > {
System.out.println("Searching...");
return n.contains("red");
};
colors.stream()
.filter(c -> c.length() > 3)
.allMatch(test);
What is the result?

Given the code fragments:
class Caller implements Callable<String> {
String str;
public Caller (String s) {this.str=s;}
public String call()throws Exception { return str.concat ("Caller");}
}
class Runner implements Runnable {
String str;
public Runner (String s) {this.str=s;}
public void run () { System.out.println (str.concat ("Runner"));}
}
and
public static void main (String[] args) InterruptedException, ExecutionException {
ExecutorService es = Executors.newFixedThreadPool(2);
Future f1 = es.submit (new Caller ("Call"));
Future f2 = es.submit (new Runner ("Run"));
String str1 = (String) f1.get();
String str2 = (String) f2.get();//line n1
System.out.println(str1+ ":" + str2);
}
What is the result?

Given:

What is the result?