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Sample Question 4
Which set of commands is necessary to create and run a custom runtime image from Java
source files?
A. java, jdeps B. javac, jlink C. jar, jlink D. javac, jar
Which statement about a functional interface is true?
A. It must be defined with the public access modifier. B. It must be annotated with @FunctionalInterface. C. It is declared with a single abstract method. D. It is declared with a single default method. E. It cannot have any private methods and static methods.
Which two statements are true about the modular JDK? (Choose two.)
A. The foundational APIs of the Java SE Platform are found in the java.base module. B. An application must be structured as modules in order to run on the modular JDK. C. It is possible but undesirable to configure modules’ exports from the command line. D. APIs are deprecated more aggressively because the JDK has been modularized.
Answer: A,C
Sample Question 7
Which two statements are true about Java modules? (Choose two.)
A. Modular jars loaded from --module-path are automatic modules. B. Any named module can directly access all classes in an automatic module. C. Classes found in –classpath are part of an unnamed module. D. Modular jars loaded from –classpath are automatic modules. E. If a package is defined in both the named module and the unnamed module, then thepackage in the unnamed module is ignored.
Which is the correct order of possible statements in the structure of a Java class file?
A. class, package, import B. package, import, class C. import, package, class D. package, class, import E. import, class, package
Answer: B
Sample Question 9
Which two are successful examples of autoboxing? (Choose two.)
A. String a = “A”; B. Integer e = 5; C. Float g = Float.valueOf(null); D. Double d = 4; E. Long c = 23L; F. Float f = 6.0;
Answer: A,B
Sample Question 10
Which three annotation uses are valid? (Choose three.)
A. Function func = (@NonNull x) > x.toUpperCase(); B. var v = “Hello” + (@Interned) “World” C. Function<String, String> func = (var @NonNull x) > x.toUpperCase(); D. Function<String, String> func = (@NonNull var x) > x.toUpperCase(); E. var myString = (@NonNull String) str; F. var obj = new @Interned MyObject();
Answer: A,C,F
Sample Question 11
Which interface in the java.util.function package will return a void return type?
Given the code fragment:var pool = Executors.newFixedThreadPool(5);Future outcome = pool.submit(() > 1);Which type of lambda expression is passed into submit()?
A. java.lang.Runnable B. java.util.function.Predicate C. java.util.function.Function D. java.util.concurrent.Callable Answer: D
Given:var fruits = List.of(“apple”, “orange”, “banana”, “lemon”);You want to examine the first element that contains the character n. Which statement willaccomplish this?
A. String result = fruits.stream().filter(f > f.contains(“n”)).findAny(); B. fruits.stream().filter(f > f.contains(“n”)).forEachOrdered(System.out::print); C. Optional<String> result = fruits.stream().filter(f > f.contains (“n”)).findFirst (); D. Optional<String> result = fruits.stream().anyMatch(f > f.contains(“n”));
Answer: B
Sample Question 14
Which statement about access modifiers is correct?
A. An instance variable can be declared with the static modifier. B. A local variable can be declared with the final modifier. C. An abstract method can be declared with the private modifier. D. An inner class cannot be declared with the public modifier. E. An interface can be declared with the protected modifier.
A. Runnable r = “Message” > System.out.println(); B. Runnable r = () > System.out::print; C. Runnable r = () -> {System.out.println(“Message”);}; D. Runnable r = > System.out.println(“Message”); E. Runnable r = {System.out.println(“Message”)};
Which two statements independently compile? (Choose two.)
A. List<? super Short> list = new ArrayList<Number>(); B. List<? super Number> list = new ArrayList<Integer>(); C. List<? extends Number> list = new ArrayList<Byte>(); D. List<? extends Number> list = new ArrayList<Object>(); E. List<? super Float> list = new ArrayList<Double>();
Answer: A,C
Sample Question 17
Which two statements set the default locale used for formatting numbers, currency, and
percentages? (Choose two.)
A. Locale.setDefault(Locale.Category.FORMAT, “zh-CN”); B. Locale.setDefault(Locale.Category.FORMAT, Locale.CANADA_FRENCH); C. Locale.setDefault(Locale.SIMPLIFIED_CHINESE); D. Locale.setDefault(“en_CA”); E. Locale.setDefault(“es”, Locale.US);
Given the Person class with age and name along with getter and setter methods, and this
code fragment:What will be the result?
A. Aman Tom Peter B. Tom Aman Peter C. Aman Peter Tom D. Tom Peter Aman
Answer: C
Sample Question 19
Given:List<String> list1 = new ArrayList<>();list1.add(“A”);list1.add(“B”);List list2 = List.copyOf(list1);list2.add(“C”);List<List<String>> list3 = List.of(list1, list2);System.out.println(list3);What is the result?
A. [[A, B],[A, B]] B. An exception is thrown at run time. C. [[A, B], [A, B, C]] D. [[A, B, C], [A, B, C]]
Answer: B
Sample Question 20
Which two commands are used to identify class and module dependencies? (Choose two.)
A. jmod describe B. java Hello.java C. jdeps --list-deps D. jar --show-module-resolution E. java --show-module-resolution
Given:public class X {}andpublic final class Y extends X {}What is the result of compiling these two classes?
A. The compilation fails because there is no zero args constructor defined in class X. B. The compilation fails because either class X or class Y needs to implement the toString() method. C. The compilation fails because a final class cannot extend another class. D. The compilation succeeds.
Answer: B
Sample Question 22
Which interface in the java.util.function package can return a primitive type?
A. ToDoubleFunction B. Supplier C. BiFunction D. LongConsumer
A. At runtime, classes are loaded as needed, and new code modules can be loaded on
demand. B. The runtime can process machine language sources as well as executables from
different language compilers. C. The Java compiler uses reflection to test if class methods are supported by resources of
a target platform D. The Java compiler preprocesses classes to run on specific target platforms.
Answer: A
Sample Question 24
Which two describe reasons to modularize the JDK? (Choose two.)
A. easier to understand the Java language B. improves security and maintainability C. easier to expose implementation details D. improves application robustness E. easier to build a custom runtime linking application modules and JDK modules
Answer: B,D
Sample Question 25
Which command line runs the main class com.acme.Main from the module com.example?
A. java --module-path mods com.example/com.acme.Main B. java –classpath com.example.jar com.acme.Main C. java --module-path mods -m com.example/com.acme.Main D. java -classpath com.example.jar –m com.example/com.acme.Main
Answer: D
Sample Question 26
Given the code fragment:Path source = Paths.get(“/repo/a/a.txt”);Path destination = Paths.get(“/repo”);Files.move(source, destination); // line 1Files.delete (source); // line 2Assuming the source file and destination folder exist, what Is the result?
A. A java.nio.file.FileAlreadyExistsException is thrown on line 1. B. A java.nio.file.NoSuchFileException is thrown on line 2. C. A copy of /repo/a/a.txt is moved to the /repo directory and /repo/a/a.txt is deleted. D. a.txt is renamed repo.
Answer: C
Sample Question 27
Which two statements correctly describe capabilities of interfaces and abstract classes?
(Choose two.)
A. Interfaces cannot have protected methods but abstract classes can. B. Both interfaces and abstract classes can have final methods. C. Interfaces cannot have instance fields but abstract classes can. D. Interfaces cannot have static methods but abstract classes can. E. Interfaces cannot have methods with bodies but abstract classes can.
A. jdbe.mysql.com://localhost:3306/database B. http://localhost.mysql.com:3306/database C. http://localhost mysql.jdbc:3306/database D. jdbc:mysql://localhost:3306/database
var numbers = List.of(0,1,2,3,4,5,6,7,8,9);
You want to calculate the average of numbers. Which two codes will accomplish this?
(Choose two.)
A. double avg = numbers.stream().parallel().averagingDouble(a > a); B. double avg = numbers.parallelStream().mapToInt (m > m).average().getAsDouble (); C. double avg = numbers.stream().mapToInt (i > i).average().parallel(); D. double avg = numbers.stream().average().getAsDouble(); E. double avg = numbers.stream().collect(Collectors.averagingDouble(n > n));
Answer: B,D
Sample Question 30
Given the contents:MessageBundle.properties file:message=HelloMessageBundle_en.properties file:message=Hello (en)MessageBundle_US.properties file:message=Hello (US)MessageBundle_en_US.properties file:message=Hello (en_US)MessageBundle_fr_FR.properties file:message=Bonjourand the code fragment:Locale.setDefault(Locale.FRANCE);Locale currentLocale = new Locale.Builder().setLanguage(“en”).build();ResourceBundle messages = ResourceBundle.getBundle(“MessageBundle”,currentLocale);System.out. println(messages.getString(“message”));Which file will display the content on executing the code fragment?
A. MessageBundle_en_US.properties B. MessageBundle_en.properties C. MessageBundle_fr_FR.properties D. MessageBundle_US.properties E. MessageBundle.properties
Which describes an aspect of Java that contributes to high performance?
A. Java prioritizes garbage collection. B. Java has a library of built-in functions that can be used to enable pipeline burst execution. C. Java monitors and optimizes code that is frequently executed. D. Java automatically parallelizes code execution.
Answer: C
Sample Question 32
Given:String originalPath = “data\\projects\\a-project\\..\\..\\another-project”;Path path = Paths.get(originalPath);System.out.print(path.normalize());What is the result?
A. data\another-project B. data\projects\a-project\another-project C. data\\projects\\a-project\\..\\..\\another-project D. data\projects\a-project\..\..\another-project
Answer: D
Sample Question 33
Given:var data = new ArrayList<>();data.add(“Peter”);data.add(30);data.add(“Market Road”);data.set(1, 25);data.remove(2);data.set(3, 1000L);System.out.print(data);What is the output?
A. [Market Road, 1000] B. [Peter, 30, Market Road] C. [Peter, 25, null, 1000] D. An exception is thrown at run time.
Answer: D
Sample Question 34
Given:LocalDate d1 = LocalDate.of(1997,2,7);DateTimeFormatter dtf =DateTimeFormatter.ofPattern( /*insert code here*/ );System.out.println(dtf.format (d1));Which pattern formats the date as Friday 7th of February 1997?
A. “eeee dd+”th of”+ MMM yyyy” B. “eeee dd'th of' MMM yyyy” C. “eeee d+”th of”+ MMMM yyyy” D. “eeee d’th of’ MMMM yyyy”
Answer: B
Sample Question 35
Which two statements are correct about try blocks? (Choose two.)
A. A try block can have more than one catch block. B. A finally block in a try-with-resources statement executes before the resources declaredare closed. C. A finally block must be immediately placed after the try or catch blocks. D. A try block must have a catch block and a finally block. E. catch blocks must be ordered from generic to specific exception types.
Answer: A,C
Sample Question 36
Which two safely validate inputs? (Choose two.)
A. Delegate numeric range checking of values to the database. B. Accept only valid characters and input values. C. Use trusted domain-specific libraries to validate inputs. D. Assume inputs have already been validated. E. Modify the input values, as needed, to pass validation.
Which two statements are correct about modules in Java? (Choose two.)
A. java.base exports all of the Java platforms core packages. B. module-info.java can be placed in any folder inside module-path. C. A module must be declared in module-info.java file. D. module-info.java cannot be empty. E. By default, modules can access each other as long as they run in the same folder.
Which describes a characteristic of setting up the Java development environment?
A. Setting up the Java development environment requires that you also install the JRE. B. The Java development environment is set up for all operating systems by default. C. You set up the Java development environment for a specific operating system when you
install the JDK D. Setting up the Java development environment occurs when you install an IDE before the JDK.
Which three guidelines are used to protect confidential information? (Choose three.)
A. Limit access to objects holding confidential information. B. Clearly identify and label confidential information. C. Manage confidential and other information uniformly. D. Transparently handle information to improve diagnostics. E. Treat user input as normal information. F. Validate input before storing confidential information. G. Encapsulate confidential information.
Given:jdeps -jdkinternals C:\workspace4\SimpleSecurity\jar\classes.jarWhich describes the expected output?
A. jdeps lists the module dependencies and the package names of all referenced JDK
internal APIs. If any are found, the suggested replacements are output in the console. B. jdeps outputs an error message that the -jdkinternals option requires either the -
summary or the - verbose options to output to the console. C. The -jdkinternals option analyzes all classes in the .jar and prints all class-level
dependencies. D. The -jdkinternals option analyzes all classes in the .jar for class-level dependencies on
JDK internal APIs. If any are found, the results with suggested replacements are output in
the console.
Answer: A
Explanation:
-jdkinternals option analyzes all classes in the .jar for class-level dependencies on JDK internal APIs. If any are found, the results with suggested replacements are output in the console.
Sample Question 41
Which code fragment does a service use to load the service provider with a Print interface?
A. private Print print = com.service.Provider.getInstance(); B. private java.util.ServiceLoader<Print> loader = ServiceLoader.load (Print.class); C. private java.util.ServiceLoader<Print> loader = new java.util.ServiceLoader<> (); D. private Print print = new com.service.Provider.PrintImpl();
Which three initialization statements are correct? (Choose three.)
A. int x = 12_34; B. short sh = (short)‘A’; C. String contact# = “(+2) (999) (232)”; D. boolean true = (4 == 4); E. float x = 1.99; F. int[][] e = {{1,1},{2,2}};
Answer: A,B,F
Exam Code: 1z0-819Exam Name: Java SE 11 DeveloperLast Update: May 03, 2024Questions: 257
