2024年最新の1z1-829問題集にはOracle Java認証済み試験問題と解答 [Q20-Q42]

2024年最新の1z1-829問題集にはOracle Java認証済み試験問題と解答

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Oracle 1Z0-829（Java SE 17 Developer）試験は、Java SE 17で作業する開発者の知識とスキルをテストするために設計されています。この認定試験は、すでにJavaプログラミングの経験を積んでおり、スキルをさらに向上させたいプロフェッショナルを対象としています。この試験に合格することで、Java SE 17の最新機能や強化機能を完全に理解し、効果的に使用して堅牢で効率的なアプリケーションを開発できることが証明されます。

Oracle 1Z0-829試験は、Java開発者にとって求められる認定資格であり、最新バージョンのJava SEに関するスキルを証明します。この認定資格は、世界的に認められ、IT業界の雇用主に高く評価されています。この認定は、開発者が効果的かつ効率的なコードを書き、堅牢でスケーラブルなアプリケーションを設計し、複雑な問題をトラブルシューティングする能力を持っていることを示します。この認定資格は、開発者のキャリアの可能性を向上させ、高収入の仕事の機会を開拓します。

 

質問 # 20
Given:

Which statement is true while the program prints GC?

• A. Only one of the objects previously referenced by t1 is eligible for garbage collection.
• B. Both the objects previously referenced by t1 are eligible for garbage collection.
• C. None of the objects are eligible for garbage collection.
• D. Only the object referenced by t2 is eligible for garbage collection.

正解：B

質問 # 21
Which statement is true about migration?

• A. The required modules migrate before the modules that depend on them in a top-down ^migration.
• B. Every module is moved to the module path in a bottom-up migration.
• C. Unnamed modules are automatic modules in a top-down migration.
• D. Every module is moved to the module path in a top-down migration.

正解：B

解説：
Explanation
The answer is B because a bottom-up migration is a strategy for modularizing an existing application by moving its dependencies to the module path one by one, starting from the lowest-level libraries and ending with the application itself. This way, each module can declare its dependencies on other modules using the module-info.java file, and benefit from the features of the Java Platform Module System (JPMS), such as reliable configuration, strong encapsulation, and service loading.
Option A is incorrect because a top-down migration is a strategy for modularizing an existing application by moving it to the module path first, along with its dependencies as automatic modules. Automatic modules are non-modular JAR files that are treated as modules with some limitations, such as not having a module descriptor or a fixed name. A top-down migration allows the application to use the module path without requiring all of its dependencies to be modularized first.
Option C is incorrect because a top-down migration does not require any specific order of migrating modules, as long as the application is moved first and its dependencies are moved as automatic modules. A bottom-up migration, on the other hand, requires the required modules to migrate before the modules that depend on them.
Option D is incorrect because unnamed modules are not automatic modules in any migration strategy.
Unnamed modules are modules that do not have a name or a module descriptor, such as classes loaded from the class path or dynamically generated classes. Unnamed modules have unrestricted access to all other modules, but they cannot be accessed by named modules, except through reflection with reduced security checks. References:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
Migrating to Modules (How and When) - JavaDeploy
Java 9 Modularity: Patterns and Practices for Developing Maintainable Applications

質問 # 22
Given the code fragment:

Which code line n1, obtains the java.io.Console object?

• A.
• B.
• C.
• D.
• E.

正解：C

解説：
The code fragment is trying to obtain the java.io.Console object, which is a class that provides methods to access the character-based console device, if any, associated with the current Java virtual machine. The correct way to obtain the Console object is to call the static method Console console() in the java.lang.System class. This method returns the unique Console object associated with the current Java virtual machine, if any. Therefore, option A is correct, as it calls System.console() and assigns it to a Console variable. Reference:
https://docs.oracle.com/javase/17/docs/api/java.base/java/io/Console.html
https://docs.oracle.com/javase/17/docs/api/java.base/java/lang/System.html#console()
https://education.oracle.com/products/trackp_OCPJSE17
https://mylearn.oracle.com/ou/learning-path/java-se-17-developer/99487

質問 # 23
Given:

What is the result?

• A. User name (EN)
• B. User name (EN - US)
• C. UserName
• D. The program throws a MissingResourceException.
• E. User name (US)

正解：D

解説：
The answer is B because the code fragment contains a logical error that causes a MissingResourceException at runtime. The code fragment tries to load a resource bundle with the base name "Captions.properties" and the locale "en_US". However, there is no such resource bundle available in the classpath. The available resource bundles are:
Captions.properties
Captions_en.properties
Captions_US.properties
Captions_en_US.properties
The ResourceBundle class follows a fallback mechanism to find the best matching resource bundle for a given locale. It first tries to find the resource bundle with the exact locale, then it tries to find the resource bundle with the same language and script, then it tries to find the resource bundle with the same language, and finally it tries to find the default resource bundle with no locale. If none of these resource bundles are found, it throws a MissingResourceException.
In this case, the code fragment is looking for a resource bundle with the base name "Captions.properties" and the locale "en_US". The ResourceBundle class will try to find the following resource bundles in order:
Captions.properties_en_US
Captions.properties_en
Captions.properties
However, none of these resource bundles exist in the classpath. Therefore, the ResourceBundle class will throw a MissingResourceException.
To fix this error, the code fragment should use the correct base name of the resource bundle family, which is "Captions" without the ".properties" extension. For example:
ResourceBundle captions = ResourceBundle.getBundle("Captions", currentLocale); This will load the appropriate resource bundle for the current locale, which is "Captions_en_US.properties" in this case. Reference:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
ResourceBundle (Java Platform SE 8 )
About the ResourceBundle Class (The Java™ Tutorials > Internationalization)

質問 # 24
Given:

Which two method invocation execute?

• A. new MyC() .m2 ();
• B. Ifnce.m3 ();
• C. IFace myclassobj = new Myc (); myclassObj.m3 ();
• D. IFace .,4():
• E. iFace mucloassObj = new Myc (); myClassObj.m4();
• F. IFace.m2();

正解：A、D

解説：
Explanation
The code given is an interface and a class that implements the interface. The interface has three methods, m1(), m2(), and m3(). The class has one method, m1(). The only two method invocations that will execute are D and E.
D is a call to the m2() method in the class, and E is a call to the m3() method in the interface. References:
https://education.oracle.com/products/trackp_OCPJSE17, 3, 4, 5

質問 # 25
Given:

What is the result?

• A. Mb
  MC
• B. Mb
• C. MA
• D. mA
• E. Mb

正解：D

解説：
Explanation
The code snippet is an example of Java SE 17 code. The code is checking if the object is an instance of class C and if it is, it will print "mC". If it is not an instance of class C, it will print "mA". In this case, the object is not an instance of class C, so the output will be "mA". References: Pattern Matching for instanceof - Oracle Help Center

質問 # 26
Given:

• A. there
• B. Compilation fails
• C. A NumberFormatException is thrown
• D. Hello

正解：B

解説：
Explanation
The code fragment will fail to compile because the parseInt method of the Integer class is a static method, which means that it can be invoked without creating an object of the class. However, the code is trying to invoke the parseInt method on an object of type Integer, which is not allowed. The correct way to invoke the parseInt method is by using the class name, such as Integer.parseInt (s). Therefore, the code fragment will produce a compilation error. References: Integer (Java SE 17 & JDK 17) - Oracle

質問 # 27
Given the code fragment:

What is the result?

• A. 2
  2
  0
• B. 1
  2
  -4
• C. 1
  1
  1
• D. 0
  B 2
  C -2

正解：A

解説：
The code fragment uses the Collections.binarySearch method to search for the string "e3" in the list. The first search returns the index of the element, which is 2. The second search returns the index of the element, which is 0. The third search returns the index of the element, which is -4. The final result is 2. Reference: Collections (Java SE 17 & JDK 17) - Oracle

質問 # 28
Given the course table:

Given the code fragment:

• A. false
• B. 0
• C. 1
• D. true

正解：D

解説：
The code fragment will execute the update statement and set the course fee of the course with ID 1021 to 5000. The executeUpdate method returns an int value that indicates the number of rows affected by the SQL statement. In this case, only one row will be updated, so the result variable will be 1. The if statement will check if the result is greater than 0, which is true, and print "Updated successfully". Therefore, the output of the code fragment is true. Reference: https://education.oracle.com/products/trackp_OCPJSE17, https://mylearn.oracle.com/ou/learning-path/java-se-17-developer/99487, https://docs.oracle.com/en/java/javase/17/docs/api/java.sql/java/sql/Statement.html#executeUpdate(java.lang.String)

質問 # 29
Given the code fragment:

abstract sealed interface SInt permits Story, Art { default String getTitle() { return "Book Title" ; }
}
Which set of class definitions compiles?

• A. Sealed interface Storty extends sInt {}
  Non-sealed class Art implements Sint {}
• B. Non-sealed interface story extends SInt {}
  Non-sealed interaface Art extends Sint {}
• C. Public interface story extends sInd {}
  Public interface Art extends SInt {}
• D. Interace story extends STnt {}
  Interface Art extends SInt {}
• E. Non-sealed interface story extends SInt {}
  Class Art implements Sint {}

正解：A

解説：
The answer is C because the code fragment given is an abstract sealed interface SInt that permits Story and Art. The correct answer is option C, which is a sealed interface Story that extends SInt and a non-sealed class Art that implements SInt. This is because a sealed interface can only be extended by the classes or interfaces that it permits, and a non-sealed class can implement a sealed interface.
Option A is incorrect because interface is misspelled as interace, and Story and Art should be capitalized as they are the names of the permitted classes or interfaces.
Option B is incorrect because public is misspelled as public, and sInd should be SInt as it is the name of the sealed interface.
Option D is incorrect because a non-sealed interface cannot extend a sealed interface, as it would violate the restriction of permitted subtypes.
Option E is incorrect because both Story and Art cannot be non-sealed interfaces, as they would also violate the restriction of permitted subtypes.
Reference:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
Sealed Classes and Interfaces in Java 15 | Baeldung
Sealed Class in Java - Javatpoint

質問 # 30
Given the code fragment:

What is the result?

• A. 2
  2
  0
• B. 0
• C. 1
  2
  -4
• D. 1
  1
  1
• E. 1
• F. 2

正解：F

解説：
Explanation
The code fragment uses the Collections.binarySearch method to search for the string "e3" in the list. The first search returns the index of the element, which is 2. The second search returns the index of the element, which is 0. The third search returns the index of the element, which is -4. The final result is
2. References: Collections (Java SE 17 & JDK 17) - Oracle

質問 # 31
Which statement is true?

• A. The Lock () method returns a boolean indicator immediately regardless if it has or has not managed to acquire the lock
• B. The tryLock () method returns a boolean indicator immediately if it has managed to acquire the lock, otherwise it waits for the lock acquisition.
• C. The tryLock () method returns a boolean indicator immediately regardless if it has or has not managed to acquire the lock.
• D. The lock () method returns a boolean indicator immediately if it has managed to acquire the lock, otherwise it waits for the lock acquisition.

正解：C

解説：
Explanation
The tryLock () method of the Lock interface is a non-blocking attempt to acquire a lock. It returns true if the lock is available and acquired by the current thread, and false otherwise. It does not wait for the lock to be released by another thread. This is different from the lock () method, which blocks the current thread until the lock is acquired, and does not return any value. References:
https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/Lock.html#tryLock(), 3, 4

質問 # 32
Given:

What is the result?

• A. A runtime exception is thrown.
• B. Compilation fails.
• C. 0
• D. 1
• E. 2
• F. Nothing is printed because of an indefinite loop.
• G. 3
• H. 4

正解：B

解説：
Explanation
The code will not compile because the variable 'x' is declared as final and then it is being modified in the switch statement. This is not allowed in Java. A final variable is a variable whose value cannot be changed once it is initialized1. The switch statement tries to assign different values to 'x' depending on the value of 'y', which violates the final modifier. The compiler will report an error: The final local variable x cannot be assigned. It must be blank and not using a compound assignment. References: The final Keyword (The Java™ Tutorials > Learning the Java Language > Classes and Objects)

質問 # 33
Assume you have an automatic module from the module path display-ascii-0.2. jar. Which name is given to the automatic module based on the given JAR file?

• A. Display.ascii
• B. Display-ascii-0
• C. Display-ascii-0.2
• D. Display-ascii

正解：D

解説：
An automatic module name is derived from the name of the JAR file when it does not contain a module-info.class file. If the JAR file has an "Automatic-Module-Name" attribute in its main manifest, then its value is the module name. Otherwise, the module name is derived from the JAR file's name by removing any version numbers and converting it to lower case. Therefore, for a JAR named display-ascii-0.2.jar, the automatic module name would be display-ascii, following these rules.

質問 # 34
Given:

What is the result?

• A. User name (EN)
• B. User name (EN - US)
• C. UserName
• D. The program throws a MissingResourceException.
• E. User name (US)

正解：D

解説：
Explanation
The answer is B because the code fragment contains a logical error that causes a MissingResourceException at runtime. The code fragment tries to load a resource bundle with the base name "Captions.properties" and the locale "en_US". However, there is no such resource bundle available in the classpath. The available resource bundles are:
Captions.properties
Captions_en.properties
Captions_US.properties
Captions_en_US.properties
The ResourceBundle class follows a fallback mechanism to find the best matching resource bundle for a given locale. It first tries to find the resource bundle with the exact locale, then it tries to find the resource bundle with the same language and script, then it tries to find the resource bundle with the same language, and finally it tries to find the default resource bundle with no locale. If none of these resource bundles are found, it throws a MissingResourceException.
In this case, the code fragment is looking for a resource bundle with the base name "Captions.properties" and the locale "en_US". The ResourceBundle class will try to find the following resource bundles in order:
Captions.properties_en_US
Captions.properties_en
Captions.properties
However, none of these resource bundles exist in the classpath. Therefore, the ResourceBundle class will throw a MissingResourceException.
To fix this error, the code fragment should use the correct base name of the resource bundle family, which is
"Captions" without the ".properties" extension. For example:
ResourceBundle captions = ResourceBundle.getBundle("Captions", currentLocale); This will load the appropriate resource bundle for the current locale, which is "Captions_en_US.properties" in this case. References:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
ResourceBundle (Java Platform SE 8 )
About the ResourceBundle Class (The Java™ Tutorials > Internationalization)

質問 # 35
Given the code fragment:

Which action enables the code to compile?

• A. Replace thye regNo variable static
• B. Make the regNo variable public
• C. Replace record with void.
• D. Remove the regNO initialization statement.
• E. Make the regNo variable static.

正解：B

解説：
Explanation
The code will compile if the regNo variable is made public. This is because the regNo variable is being accessed in the main method of the App class, which is outside the scope of the Product class. Making the regNo variable public will allow it to be accessed from outside the class. References:
https://education.oracle.com/products/trackp_OCPJSE17,
https://mylearn.oracle.com/ou/learning-path/java-se-17-developer/99487,
https://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html

質問 # 36
Given:

Which action enables the code to compile?

• A. Replace 15 with item.display (''Flower'');
• B. Replace 2 with static string name;
• C. Replace 7 with public void display (string design) {
• D. Replace 3 with private static void display () {

正解：C

解説：
Explanation
The answer is C because the code fragment contains a syntax error in line 7, where the method display is declared without any parameter type. This causes a compilation error, as Java requires the parameter type to be specified for each method parameter. To fix this error, the parameter type should be added before the parameter name, such as string design. This will enable the code to compile and run without any errors.
References:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
Java Methods

質問 # 37
Given:

Which action enables the code to compile?

• A. Replace 15 with item.display (''Flower'');
• B. Replace 2 with static string name;
• C. Replace 7 with public void display (string design) {
• D. Replace 3 with private static void display () {

正解：C

解説：
The answer is C because the code fragment contains a syntax error in line 7, where the method display is declared without any parameter type. This causes a compilation error, as Java requires the parameter type to be specified for each method parameter. To fix this error, the parameter type should be added before the parameter name, such as string design. This will enable the code to compile and run without any errors. Reference:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
Java Methods

質問 # 38
Given:

What is the result?

• A. 101
  101
  1000
• B. 1001
  1001
  1000
• C. 1001
  100
  1000
• D. 100
  100
  1000

正解：C

解説：
Explanation
The code fragment is using the bitwise operators & (AND), | (OR), and ^ (XOR) to perform operations on the binary representations of the integer values. The & operator returns a 1 in each bit position where both operands have a 1, the | operator returns a 1 in each bit position where either operand has a 1, and the ^ operator returns a 1 in each bit position where only one operand has a 1. The binary representations of the integer values are as follows:
1000 = 1111101000
100 = 1100100
101 = 1100101
The code fragment performs the following operations:
x = x ^ y; // x becomes 1111010101, which is 1001 in decimal
y = x ^ y; // y becomes 1100100, which is 100 in decimal
x = x ^ y; // x becomes 1100101, which is 101 in decimal
The code fragment then prints out the values of x, y, and z, which are 1001, 100, and 1000 respectively.
Therefore, option D is correct.

質問 # 39
Given the code fragments:

Which action prints Wagon : 200?

• A. At Line n1, implement the java.io.AutoCloseable interface
• B. At line n3, replace readObject (0 with readLine().
• C. At line n2, in the main method signature, add throws IOException, ClassCastException.
• D. At Line n3, replace Car with LuxurayCar.
• E. At line n2, in the main method signature, add throws IoException, ClassNotFoundException.
• F. At line n1, implement the java.io, Serializable interface.

正解：E

解説：
Explanation
The code fragment is trying to read an object from a file using the ObjectInputStream class. This class throws an IOException and a ClassNotFoundException. To handle these exceptions, the main method signature should declare that it throws these exceptions. Otherwise, the code will not compile. If the main method throws these exceptions, the code will print Wagon : 200, which is the result of calling the toString method of the LuxuryCar object that was written to the file. References: ObjectInputStream (Java SE 17 & JDK 17) - Oracle, ObjectOutputStream (Java SE 17 & JDK 17) - Oracle

質問 # 40
Given:

What is the result?

• A. Mb
  MC
• B. Mb
• C. MA
• D. mA
• E. Mb

正解：D

解説：
The code snippet is an example of Java SE 17 code. The code is checking if the object is an instance of class C and if it is, it will print "mC". If it is not an instance of class C, it will print "mA". In this case, the object is not an instance of class C, so the output will be "mA". Reference: Pattern Matching for instanceof - Oracle Help Center

質問 # 41
Given the code fragment:

What is the result?

• A. Range 1
• B. Range1
  Note a valid rank.
• C. Range 1
  Range 2
  Range 3
• D. Range 1
  Range 2
  Range 3
  Range 1
  Not a valida rank

正解：D

解説：
The code fragment is using the switch statement with the new Java 17 syntax. The switch statement checks the value of the variable rank and executes the corresponding case statement. In this case, the value of rank is 4, so the first case statement is executed, printing "Range1". The second and third case statements are also executed, printing "Range2" and "Range3". The default case statement is also executed, printing "Not a valid rank". Reference: Java Language Changes - Oracle Help Center

質問 # 42
......

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