Oracle 1z0-819 Dumps

Question # 1

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

Show Answer

Question # 2

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.

Show Answer

Question # 3

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.

Show Answer

Question # 4

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.

Show Answer

Question # 5

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

Show Answer

Question # 6

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;

Show Answer

Question # 7

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();

Show Answer

Question # 8

Which interface in the java.util.function package will return a void return type? 

A. Supplier
B. Predicate
C. Function
D. Consumer

Show Answer

Question # 9

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

Show Answer

Question # 10

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”));

Show Answer

Question # 11

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.

Show Answer

Question # 12

Which code is correct? 

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”)};

Show Answer

Question # 13

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>();

Show Answer

Question # 14

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);

Show Answer

Question # 15

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

Show Answer

Question # 16

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]]

Show Answer

Question # 17

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

Show Answer

Question # 18

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.

Show Answer

Question # 19

Which interface in the java.util.function package can return a primitive type? 

A. ToDoubleFunction
B. Supplier
C. BiFunction
D. LongConsumer

Show Answer

Question # 20

What makes Java dynamic? 

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.  

Show Answer