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Java MCQ: What is the behavior of the Map.of() method when invoked with duplicate keys? a) It merges the values of the duplicate keys b) It replaces the previous key with the new one c) It throws an IllegalArgumentException d) It removes the duplicate key Answer: c) It throws an IllegalArgumentException Explanation: The Map.of() method […]

Java MCQ: Which of the following is true about the Map.ofEntries() method in Java 9? a) It creates a mutable map with a fixed number of entries b) It allows the creation of an immutable map with more than 10 entries c) It creates a map that allows null keys and values d) It replaces

Java MCQ: What is the correct way to define a module in Java 9? a) Using the module keyword in a file named module-info.java b) Using the class keyword in a file named module.java c) Using the package keyword in a file named module.java d) Using the interface keyword in a file named module-info.java Answer:

Java MCQ: Which method in Java 9 is used to create an immutable Map with a variable number of key-value pairs? a) Map.put() b) Map.ofEntries() c) Map.copyOf() d) Map.of() Answer: d) Map.of() Explanation: The Map.of() method introduced in Java 9 is used to create an immutable Map with a variable number of key-value pairs. This

Java MCQ: Which of the following best describes the purpose of the Set.of() method in Java 9? a) To create a mutable set b) To create an immutable set c) To create a set with duplicate elements d) To convert a list to a set Answer: b) To create an immutable set Explanation: The Set.of()

Java MCQ: What happens if you use the Java 9 List.of() method with null elements? a) It creates a List with null elements b) It creates a List and removes the null elements c) It throws a NullPointerException d) It converts null elements to empty strings Answer: c) It throws a NullPointerException Explanation: Using the

Java MCQ: Which statement is true about private methods in interfaces introduced in Java 9? a) They can be called from outside the interface b) They can only be called within default or static methods of the same interface c) They must be overridden by implementing classes d) They are automatically public Answer: b) They

Java MCQ: How do you start a JShell session from the command line? a) Run the command java -jshell b) Run the command jshell c) Run the command java -jar jshell.jar d) Run the command shelljava Answer: b) Run the command jshell Explanation: To start a JShell session from the command line, you run the

Java MCQ: What is a key advantage of using Java modules introduced in Java 9? a) They allow for direct memory access b) They enable better encapsulation and modularization of code c) They improve exception handling d) They increase the speed of the garbage collector Answer: b) They enable better encapsulation and modularization of code

Java MCQ: What is the result of using the Java 9 method Set.of() with duplicate elements? a) It creates a Set with duplicate elements b) It creates a Set with the duplicates removed c) It throws an IllegalArgumentException d) It sorts the elements and removes duplicates Answer: c) It throws an IllegalArgumentException Explanation: Using the

Java MCQ: How does the module-info.java file contribute to Java 9’s module system? a) It specifies dependencies and defines module boundaries b) It replaces the main class in a Java application c) It is used for logging configuration d) It provides metadata for JAR files Answer: a) It specifies dependencies and defines module boundaries Explanation:

Java MCQ: What is a key benefit of using the JShell tool introduced in Java 9? a) It improves application performance b) It allows for interactive experimentation with Java code c) It replaces the Java compiler d) It provides a graphical user interface for Java development Answer: b) It allows for interactive experimentation with Java

Java MCQ: Which Java 9 method is used to create an immutable map with multiple entries? a) Map.of() b) Map.copyOf() c) Map.ofEntries() d) Map.unmodifiable() Answer: c) Map.ofEntries() Explanation: The Map.ofEntries() method, introduced in Java 9, is used to create an immutable map with multiple entries. This method is similar to Map.of() but allows for the

Java MCQ: Which method introduced in Java 9 allows the creation of an immutable Set? a) Set.copyOf() b) Set.of() c) Set.unmodifiable() d) Set.immutable() Answer: b) Set.of() Explanation: The Set.of() method, introduced in Java 9, allows the creation of an immutable Set. An immutable set is a set that cannot be modified after it is created,

Java MCQ: What is the purpose of the Java 9 List.of() method? a) To create a mutable List b) To create an immutable List c) To convert a List to a Set d) To sort a List Answer: b) To create an immutable List Explanation: The List.of() method introduced in Java 9 is used to

Java MCQ: Which new feature in Java 9 allows interfaces to have private methods? a) Private constructors b) Private methods in interfaces c) Private fields d) Private inner classes Answer: b) Private methods in interfaces Explanation: Java 9 introduced the ability to define private methods in interfaces. This feature allows interfaces to have methods that

Java MCQ: Which Java 9 feature allows developers to interactively evaluate code snippets? a) JavaFX b) JShell c) JConsole d) Javadoc Answer: b) JShell Explanation: JShell is a feature introduced in Java 9 that allows developers to interactively evaluate code snippets. JShell, also known as the REPL (Read-Eval-Print Loop) tool, provides an environment where developers

Java MCQ: What is the primary purpose of the Java Module System introduced in Java 9? a) To improve multithreading capabilities b) To encapsulate packages and improve code organization c) To replace the JDK d) To enhance the GUI framework Answer: b) To encapsulate packages and improve code organization Explanation: The primary purpose of the

Java MCQ: What is the result of using the Java 9 method Set.of() with duplicate elements? a) It creates a Set with duplicate elements b) It creates a Set with the duplicates removed c) It throws an IllegalArgumentException d) It sorts the elements and removes duplicates Answer: c) It throws an IllegalArgumentException Explanation: Using the

Java MCQ: How does the module-info.java file contribute to Java 9’s module system? a) It specifies dependencies and defines module boundaries b) It replaces the main class in a Java application c) It is used for logging configuration d) It provides metadata for JAR files Answer: a) It specifies dependencies and defines module boundaries Explanation:

Java MCQ: What is a key benefit of using the JShell tool introduced in Java 9? a) It improves application performance b) It allows for interactive experimentation with Java code c) It replaces the Java compiler d) It provides a graphical user interface for Java development Answer: b) It allows for interactive experimentation with Java

Java MCQ: Which Java 9 method is used to create an immutable map with multiple entries? a) Map.of() b) Map.copyOf() c) Map.ofEntries() d) Map.unmodifiable() Answer: c) Map.ofEntries() Explanation: The Map.ofEntries() method, introduced in Java 9, is used to create an immutable map with multiple entries. This method is similar to Map.of() but allows for the

Java MCQ: Which method introduced in Java 9 allows the creation of an immutable Set? a) Set.copyOf() b) Set.of() c) Set.unmodifiable() d) Set.immutable() Answer: b) Set.of() Explanation: The Set.of() method, introduced in Java 9, allows the creation of an immutable Set. An immutable set is a set that cannot be modified after it is created,

Java MCQ: What is the purpose of the Java 9 List.of() method? a) To create a mutable List b) To create an immutable List c) To convert a List to a Set d) To sort a List Answer: b) To create an immutable List Explanation: The List.of() method introduced in Java 9 is used to

Java MCQ: Which new feature in Java 9 allows interfaces to have private methods? a) Private constructors b) Private methods in interfaces c) Private fields d) Private inner classes Answer: b) Private methods in interfaces Explanation: Java 9 introduced the ability to define private methods in interfaces. This feature allows interfaces to have methods that