Given the code fragment: List<String> words = Arrays.asList("win", "try", "best", "luck", "do"); Predicate<String> test1 = w -> { System.out.println("Checking..."); // line n1 return w.equals("do")…

The correct answer is C. Checking... Checking. Option C is correct because the two filters are chained: test2 (length > 3) passes exactly two words - "best" and "luck" - and then test1 executes on each of those two survivors, printing "Checking..." once per element, giving two printed lines. Why the distractors are wrong: A…

Question

Given the code fragment:
List<String> words = Arrays.asList("win", "try", "best", "luck", "do");
Predicate<String> test1 = w -> {
System.out.println("Checking..."); // line n1
return w.equals("do");
};
Predicate test2 = (String w) -> w.length() > 3; // line n2
words.stream()
.filter(test2)
.filter(test1)
.count();
What is the result?

Options

AA compilation error occurs at line n1.
BChecking...
CChecking... Checking...
DA compilation error occurs at line n2.

How the community answered

(67 responses)

A
9% (6)
B
3% (2)
C
75% (50)
D
13% (9)

Explanation

Option C is correct because the two filters are chained: test2 (length > 3) passes exactly two words - "best" and "luck" - and then test1 executes on each of those two survivors, printing "Checking..." once per element, giving two printed lines.

Why the distractors are wrong:

A - No error at line n1; a Predicate<String> lambda with a block body containing System.out.println is perfectly legal Java.
B - Only one line would print if only one word survived test2, but both "best" and "luck" have length 4 (> 3), so two words reach test1.
D - Predicate (raw type) at line n2 generates an unchecked warning, not a compilation error; the explicit (String w) type annotation in the lambda keeps it compilable.

Memory tip: When filters are chained, mentally run each filter as a "gate" and count how many elements exit the last gate before the print - that count equals how many times the println fires.

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