Free Java SE 11 Developer Exam 1Z0-819 Exam Practice Test

Which code fragment does a service use to load the service provider with a Print interface?

• private Print print = com.service.Provider.getInstance();
• private java.util.ServiceLoader<Print> loader = ServiceLoader.load (Print.class);
• private java.util.ServiceLoader<Print> loader = new java.util.ServiceLoader<> ();
• private Print print = new com.service.Provider.PrintImpl();

Which two statements are correct about modules in Java? (Choose two.)

• java.base exports all of the Java platforms core packages.
• module-info.java can be placed in any folder inside module-path.
• A module must be declared in module-info.java file.
• module-info.java cannot be empty.
• By default, modules can access each other as long as they run in the same folder.

Given:jdeps -jdkinternals C:\workspace4\SimpleSecurity\jar\classes.jarWhich describes the expected output?

• 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.
• jdeps outputs an error message that the -jdkinternals option requires either the -summary or the - verbose options to output to the console.
• The -jdkinternals option analyzes all classes in the .jar and prints all class-level dependencies.
• 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.

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.)

• double avg = numbers.stream().parallel().averagingDouble(a > a);
• double avg = numbers.parallelStream().mapToInt (m > m).average().getAsDouble ();
• double avg = numbers.stream().mapToInt (i > i).average().parallel();
• double avg = numbers.stream().average().getAsDouble();
• double avg = numbers.stream().collect(Collectors.averagingDouble(n > n));

Which two statements correctly describe capabilities of interfaces and abstract classes? (Choose two.)

• Interfaces cannot have protected methods but abstract classes can.
• Both interfaces and abstract classes can have final methods.
• Interfaces cannot have instance fields but abstract classes can.
• Interfaces cannot have static methods but abstract classes can.
• Interfaces cannot have methods with bodies but abstract classes can.

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

• Supplier
• Predicate
• Function
• Consumer

Which two safely validate inputs? (Choose two.)

• Delegate numeric range checking of values to the database.
• Accept only valid characters and input values.
• Use trusted domain-specific libraries to validate inputs.
• Assume inputs have already been validated.
• Modify the input values, as needed, to pass validation.

Which three annotation uses are valid? (Choose three.)

• Function<String, String> func = (@NonNull x) > x.toUpperCase();
• var v = ''Hello'' + (@Interned) ''World''
• Function<String, String> func = (var @NonNull x) > x.toUpperCase();
• Function<String, String> func = (@NonNull var x) > x.toUpperCase();
• var myString = (@NonNull String) str;
• var obj = new @Interned MyObject();

Which statement about a functional interface is true?

• It must be defined with the public access modifier.
• It must be annotated with @FunctionalInterface.
• It is declared with a single abstract method.
• It is declared with a single default method.
• It cannot have any private methods and static methods.

Which two commands are used to identify class and module dependencies? (Choose two.)

• jmod describe
• java Hello.java
• jdeps --list-deps
• jar --show-module-resolution
• java --show-module-resolution