1z0-813.exam.28q 1z0-813 Upgrade to Java SE 8 OCP (Java SE 6 and all prior versions)

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1 1z0-813.exam.28q Number: 1z0-813 Passing Score: 800 Time Limit: 120 min 1z0-813 Upgrade to Java SE 8 OCP (Java SE 6 and all prior versions)

2 Exam A QUESTION 1 Given the code fragment: What is the result? A. [x, x] [x, x, x, x] B. [x, x]

3 C. [x] [x, x] [x, x, x] D. [x] [x, x] [x, x, x] [x, x, x, x] Correct Answer: D /Reference: : CyclicBarrier is a synchronization aid that allows a set of threads to all wait for each other to reach a common barrier point. CyclicBarriers are useful in programs involving a fixed sized party of threads that must occasionally wait for each other. The barrier is called cyclic because it can be re-used after the waiting threads are released. Reference: QUESTION 2 In daylight saving time in New York, USA, begins on March 8th at 2:00 AM. As a result, 2:00 AM becomes 3:00 AM. Given the code fragment: Which is the result? A. 2:00 difference: 1 B. 3:00 difference: 2 C. 4:00 difference: 3 D. 4:00 difference: 2

4 Correct Answer: D /Reference: Reference: QUESTION 3 Which is true the regarding the java.nio.file.path interface? A. Implementations of this interface are not safe for use by multiple concurrent threads. B. The interface extends the WatchService interface. C. Implementations of this interface are immutable. D. Paths associated with the default provider are not interoperable with the java.io.file class. Correct Answer: B /Reference: : This interface extends Watchable interface so that a directory located by a path can be registered with a WatchService and entries in the directory watched. Reference: QUESTION 4 Given:

5 and the code fragment: What is the result? A. A compilation error occurs. B C D. 0.0 Correct Answer: A

6 /Reference: : The line maptoint(person::getsalary) will cause a compile error. If it is replaced by the following line, a "." is added in the beginning of the line, the result would be :.mapToInt(Person::getSalary) QUESTION 5 Which two codes correctly represent a standard language locale code? (Choose two.) A. u8 B. fr C. es D. U8 E. FR F. ES Correct Answer: BC /Reference: : Language codes use lowercase. The following examples create Locale objects for the French language in Canada, the English language in the U.S. and Great Britain. alocale = new Locale("fr", "CA"); blocale = new Locale("en", "US"); clocale = new Locale("en", "GB"); Reference: QUESTION 6 Given the code fragment:

7 What is the result? A. 0 0 B. 1 2 C. 1 4 D. A compilation error occurs Correct Answer: D /Reference: : A compilation error will occur at the following line: map.compute("1", (k, v) -> (v == null)? k * k : 0 ); The error is: Exception in thread "main" java.lang.runtimeexception: Uncompilable source code - bad operand types for binary operator '*' first type: java.lang.string second type: java.lang.string QUESTION 7 Given the incomplete pseudo-code for a fork/join framework application:

8 And given the missing methods: process, submit, and splitinhalf Which three insertions properly complete the pseudo-code? (Choose three.) A. Insert process at line Z. B. Insert process at line X. C. Insert submit at line X. D. Insert splitinhalf at line X. E. Insert process at line Y. F. Insert splitinhalf at line Y. G. Insert submit at line Z. Correct Answer: BFG /Reference: : B: If the size is small enough then process the work. D: If the size is not small enough then slit up the wok in half. G: Submit the two split up pieces of work recursively.

9 Note: Your code should look similar to the following pseudocode: Reference: QUESTION 8 Given the code fragment: Which code fragment, when inserted at line n1, enables the code to print the count of string elements whose length is greater than three? A. listval.stream().filter(x -> x.length() > 3).count() B. listval.stream().map(x -> x.length() > 3).count() C. listval.stream().peek(x -> x.length() > 3).count().get() D. listval.stream().filter(x -> x.length() > 3).mapToInt(x -> x).count() Correct Answer: A /Reference: : Gives the correct output of 2. Incorrect Answers: B: Output is 4.

10 C, D: Does not compile. QUESTION 9 Given the code fragments: and What is the result? A. A compilation error occurs at line n2. B. The program prints Run and throws an exception. C. Run Call

11 D. A compilation errors occurs at line n1. Correct Answer: A /Reference: QUESTION 10 Given the code fragments: and What is the result? A. An exception is thrown at runtime. B. A compilation error occurs.

12 C. Jack Jane D. Jack Jane John Tom Tim Correct Answer: A /Reference: : p is not recognized in the line: persons.foreach -> System.out.print(p.getName() + " "); and an exception is thrown at runtime. Exception in thread "main" java.lang.runtimeexception: Uncompilable source code - not a statement QUESTION 11 Given the code fragment: Which code fragment, when inserted at line n1, enables the code to print [500,1000]? A. Function<Integer> funintf = n -> n * 5; B. Consumer<Integer> funintf = n -> n * 5; C. UnaryOperator<Integer> funintf = n -> n * 5; D. IntFuction funintf = n -> n * 5; Correct Answer: C /Reference:

13 QUESTION 12 Given the following incorrect program: Which two changes make the program work correctly? (Choose two.) A. The MyTask class must be modified to extend RecursiveAction instead of RecursiveTask. B. The computedirectly() method must be enhanced to fork() newly created tasks. C. The compute() method must be changed to return an Integer result. D. The THRESHOLD value must be increased so that the overhead of task creation does not dominate the cost of computation. E. Results must be retrieved from the newly created MyTask instances and combined. F. The midpoint computation must be altered so that it splits the workload in an optimal manner. Correct Answer: CE /Reference: : The compute() method must return an Integer result. The results of the InvokeAll tasks must be combined. Incorrect Answers: A: RecursiveAction is just like RecursiveTask except it does not return a result

14 F: The Midpoint, mid = (low + high)/2, is fine. Reference: QUESTION 13 Given: and the code fragment: Which two code fragments, when inserted at line n1 independently, enable the code print TruckCarBike? (Choose two.) A..sorted(Comparable.comparing(Vehicle::getVName)).reversed() B..sorted((v1, v2) -> Integer.compare(v1.getVId(), v2.getvid())) C..sorted((v1, v2) -> v1.getvid() < v2.getvid()) D..map(v -> v.getvid())

15 .sorted() E..sorted(Comparator.comparing((Vehicle v) -> v.getvid())) Correct Answer: BE /Reference: QUESTION 14 Which statement is true about java.util.stream.stream? A. All Stream operations are lazy. B. Objects in streams are intended to be mutable. C. Streams support aggregate operations. D. Streams can be reused. Correct Answer: A /Reference: : Streams are lazy; computation on the source data is only performed when the terminal operation is initiated, and source elements are consumed only as needed. Incorrect Answers: B, C: Streams do not provide a means to directly access or manipulate their elements, and are instead concerned with declaratively describing their source and the computational operations. D: A stream should be operated on (invoking an intermediate or terminal stream operation) only once. This rules out, for example, "forked" streams, where the same source feeds two or more pipelines, or multiple traversals of the same stream. A stream implementation may throw IllegalStateException if it detects that the stream is being reused. However, since some stream operations may return their receiver rather than a new stream object, it may not be possible to detect reuse in all cases. Reference: QUESTION 15 Which two elements must be present in any valid pipeline? (Choose two.)

16 A. a lambda expression or a method reference B. a source C. one or more intermediate operations D. a reduction operation E. a terminal operation Correct Answer: BE /Reference: : A stream pipeline consists of a source (such as a Collection, an array, a generator function, or an I/O channel); followed by zero or more intermediate operations such as Stream.filter or Stream.map; and a terminal operation such as Stream.forEach or Stream.reduce. Reference: QUESTION 16 You are asked to implement an interface that processes a batch of transaction objects and returns a discounted value for each transaction as a double primitive value. Which interface can you use to accomplish this task? A. ToDoubleFunction B. DoubleSupplier C. DoubleFunction D. DoubleConsumer Correct Answer: A /Reference: : The Interface ToDoubleFunction is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference. It represents a function that produces a double-valued result. This is the double-producing primitive specialization for Function.

17 Incorrect Answers: B: The Interface DoubleSupplier is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference. It represents a supplier of double-valued results. This is the double-producing primitive specialization of Supplier. C: The Interface DoubleFunction is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference. It represents a function that accepts a double-valued argument and produces a result. D: The Interface DoubleConsumer represents an operation that accepts a single double-valued argument and returns no result. Reference: QUESTION 17 Given the code fragment: Which two changes, taken together, enable the use of this class in a try-with-resources statement? (Choose two.) A. public class CustomRecourse extends AutoCloseable { B. public class CustomResource implements Closeable { C. public class CustomResource extends Closeable implements AutoCloseable { D. Add a method: public void autoclose() throws IOException { } E. Add a method: public boolean close() throws IOException { } F. Add a method: public void close() throws IOException { } Correct Answer: BF

18 /Reference: : A Closeable is a source or destination of data that can be closed. The close method is invoked to release resources that the object is holding (such as open files). It closes this stream and releases any system resources associated with it. If the stream is already closed then invoking this method has no effect. It throws an IOException - if an I/O error occurs. Reference: QUESTION 18 Given the definitions of Readable and Writable interfaces: Given:

19 What is the result? A. Compilation fails due to an error at line n3. B. Compilation fails due to an error at line n1. C. Hello Welcome Close D. Compilation fails due to an error at line n2. Correct Answer: A /Reference: : Uncompilable source code - Uncompilable source code - Erroneous sym type: Writable.close at Writable.close(); // line n3. QUESTION 19 Given the code fragment:

20 Which two code fragments, when inserted at line n1 independently, result in the output PEEK: Unix? (Choose two.) A..noneMatch(); B..anyMatch(); C..allMatch(); D..findFirst(); E..findAny(); Correct Answer: DE /Reference: : The findxxx methods, FinFirst() and findany, take no arguments and return an Optional object with the result, or an empty Optional if nothing is found. Incorrect Answers: A, B, C: XXXMatch methods. Take a Predicate and return a boolean if an element in the stream returns true by applying the Predicate. Reference: QUESTION 20 Given the code fragment: What type of result is printed? A. Time of the Epoch (in milliseconds) B. Julian date C. Era D. Time zone abbreviation

21 E. Full-text time zone name Correct Answer: E /Reference: : Output could be: Result: Central European Time Note: To make the code work you would need the following code which get today's date in Java. Date today = new Date(); Reference: QUESTION 21 Given the code fragments: and

22 What is the result? A. Java SE: Java ME:120.0 B. Java SE:300.0 Java ME:120.0 C. Compilation fails due to an error at line 15. D. Compilation fails due to an error at line 16. Correct Answer: D /Reference: : Uncompilable source code - Erroneous tree type: <any> at line: books.foreach(b -> System.out.println(b.name + ":" + b.price)); To make the code compile we would change the name reference to bname: books.foreach(b -> System.out.println(b.bname + ":" + b.price)); Note: To make the code work we would need etter and getter methods: QUESTION 22 Given code fragments:

23 and What is the result? A. [Dog, Cat, Mouse] B. DogCatMouse C. null D. A compilation error occurs. Correct Answer: D /Reference: : A compilation error: Uncompilable source code - Erroneous sym type: java.util.list.foreach at line: t.getlist().foreach(test::printvalues); QUESTION 23 Which two states are valid for a watch key? (Choose two.)

24 A. Does Not Exist B. Signalled C. Ready D. Not Runnable E. Runnable Correct Answer: BC /Reference: : A watch key has a state. When initially created the key is said to be ready. When an event is detected then the key is signalled and queued so that it can be retrieved by invoking the watch service's poll or take methods. Once signalled, a key remains in this state until its reset method is invoked to return the key to the ready state. Reference: QUESTION 24 Given:

25 and the code fragment: Which code fragment, when inserted at line n1, enables the Birdie class to compile? A. B. C. D. Correct Answer: C /Reference: QUESTION 25 Given:

26 What is the result? A B C D Correct Answer: D /Reference: QUESTION 26 Given the code fragment:

27 Which two code fragments, when inserted independently at line 6, enable the code to print true? (Choose two.) A. boolean b = nums.stream().nonematch(n -> n==20); B. boolean b = nums.stream().filter(n -> n == 20).allMatch(n -> n == 20); C. boolean b = nums.stream().filter(n -> n == 20).noneMatch(n -> n == 20); D. boolean b = nums.stream().map(n -> 20).noneMatch(n -> n == 10); E. boolean b = nums.stream().allmatch(n -> n == 20); Correct Answer: BD /Reference: QUESTION 27 Given the code fragment:

28 What is the result? A. A compilation error occurs at line n1. B. Can't logout C. Logged out at: T21:58:19.880Z D. Logged out at: T21:58:00Z Correct Answer: B /Reference: :

29 logintime and logouttime would be the same as they are truncated. QUESTION 28 Given the code fragment: You have been asked to define the ProductCode class. The definition of the ProductCode class must allow c1 instantiation to succeed and cause a compilation error on c2 instantiation. Which definition of ProductCode meets the requirement? A. class ProductCode<T, S<Integer>> { T c1; S c2; } B. class ProductCode<T, S extends T> { T c1; S c2; } C. class ProductCode<T, S> { T c1; S c2; } D. class ProductCode<T, S super T> { T c1; S c2; } Correct Answer: B /Reference:

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