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

The code fragment compares four pairs of strings using the equals() and intern() methods. The

equals() method compares the content of two strings, while the intern() method returns a canonical

representation of a string, which means that it returns a reference to an existing string with the same

content in the string pool. The string pool is a memory area where strings are stored and reused to

save space and improve performance. The results of the comparisons are as follows:

s1.equals(s2): This returns true because both s1 and s2 have the same content, “Hello Java 17”.

s1 == s2: This returns false because s1 and s2 are different objects with different

, even

though they have the same content. The == operator compares the references of two objects, not

their content.

s1.intern() == s2.intern(): This returns true because both s1.intern() and s2.intern() return a reference

to the same string object in the string pool, which has the content “Hello Java 17”. The intern()

method ensures that there is only one copy of each distinct string value in the string pool.

“Hello Java 17” == s2: This returns false because “Hello Java 17” is a string literal, which is

automatically interned and stored in the string pool, while s2 is a string object created with the new

operator, which is not interned by default and stored in the heap. Therefore, they have different

references and are not equal using the == operator.

Reference: String (Java SE 17 & JDK 17) - Oracle

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/learningpath/java-se-17-developer/99487,

https://docs.oracle.com/en/java/javase/17/docs/api/java.sql/java/sql/Statement.html#executeUpda

te(java.lang.String)

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

The answer is C because the code fragment uses a different syntax and logic for the reduce operation

than the other options. The reduce method in option C takes a single parameter, which is a

BinaryOperator that combines two elements of the stream into one. The method returns an

Optional, which may or may not contain a value depending on whether the stream is empty or not.

The code fragment then adds 5 to the result of the reduce method, regardless of whether it is

present or not. This may cause an exception if the Optional is empty, or produce a different value

than the other options if the Optional is not empty.

The other options use a different syntax and logic for the reduce operation. They all take two

parameters, which are an identity value and a BinaryOperator that combines an element of the

stream with an accumulator. The method returns the final accumulator value, which is equal to the

identity value if the stream is empty, or the result of applying the BinaryOperator to all elements of

the stream otherwise. The code fragments then add 5 to the result of the reduce method, which will

always produce a valid value.

For example, suppose listOfNumbers contains [1, 2, 3]. Then, option A will perform the following

steps:

Initialize accumulator to identity value 5

Apply BinaryOperator Integer::sum to accumulator and first element: 5 + 1 = 6

Update accumulator to 6

Apply BinaryOperator Integer::sum to accumulator and second element: 6 + 2 = 8

Update accumulator to 8

Apply BinaryOperator Integer::sum to accumulator and third element: 8 + 3 = 11

Update accumulator to 11

Return final accumulator value 11

Add 5 to final accumulator value: 11 + 5 = 16

Option B will perform the same steps as option A, except using a lambda expression instead of a

method reference for the BinaryOperator. Option D will perform the same steps as option A, except

using parallelStream instead of stream, which may change the order of applying the BinaryOperator

but not the final result. Option E will perform the same steps as option A, except using identity value

0 instead of 5.

Option C, however, will perform the following steps:

Apply BinaryOperator Integer::sum to first and second element: 1 + 2 = 3

Apply BinaryOperator Integer::sum to previous result and third element: 3 + 3 = 6

Return Optional containing final result value 6

Add 5 to Optional value: Optional.of(6) + 5 = Optional.of(11)

As you can see, option C produces a different value than the other options, and also uses a different

syntax and logic for the reduce operation. Reference:

Oracle Certified Professional: Java SE 17 Developer

Java SE 17 Developer

OCP Oracle Certified Professional Java SE 17 Developer Study Guide

Guide to Stream.reduce()

The code fragment will fail to compile because the readObject method in the Product class is missing

the @Override annotation. The readObject method is a special method that is used to customize the

deserialization process of an object. It must be declared as private, have no return type, and take a

single parameter of type ObjectInputStream. It must also be annotated with @Override to indicate

that it overrides the default behavior of the ObjectInputStream class. Without the @Override

annotation, the compiler will treat the readObject method as a normal method and not as a

deserialization

hook.

Therefore,

the

code

fragment

will

produce

a

compilation

error. Reference: Object Serialization - Oracle, [ObjectInputStream (Java SE 17 & JDK 17) - Oracle]

The code fragment is creating a string variable “a” with the value “Hello! Java”. Then, it is printing the

index of “Java” in “a”. Next, it is replacing “Hello!” with “Welcome!” in “a”. Then, it is printing the

index of “Java” in “a”. Finally, it is creating a new StringBuilder object “b” with the value of “a” and

printing the index of “Java” in “b”. The output will be 8109 because the index of “Java” in “a” is 8, the

index of “Java” in “a” after replacing “Hello!” with “Welcome!” is 10, and the index of “Java” in “b” is

9. Reference: Oracle Java SE 17 Developer source and documents: [String (Java SE 17 & JDK 17)],

[StringBuilder (Java SE 17 & JDK 17)]

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. Reference: The final Keyword (The Java™ Tutorials > Learning the Java Language > Classes and Objects)

The answer is C because the code demonstrates the concept of method overloading and type

conversion in Java. Method overloading allows different methods to have the same name but

different parameters. Type conversion allows values of one data type to be assigned to another data

type, either automatically or explicitly. In the code, the class Test has four methods named sum, each

with different parameter types: int, float, and double. The main method creates an instance of Test

and calls the sum method with different arguments. The compiler will choose the most specific

method that matches the arguments, based on the following rules:

If there is an exact match between the argument types and the parameter types, that method is

chosen.

If there is no exact match, but there is a method with compatible parameter types, that method is

chosen. Compatible types are those that can be converted from one to another automatically, such

as int to long or float to double.

If there is more than one method with compatible parameter types, the most specific method is

chosen. The most specific method is the one whose parameter types are closest to the argument

types in terms of size or precision.

In the code, the following method calls are made:

test.sum(10, 10.5) -> This matches the sum(int a, float b) method exactly, so it is chosen. The result is

20.5, which is converted to int and printed as 20 (B).

test.sum(10) -> This does not match any method exactly, but it matches the sum(double a) method

with compatible types, as int can be converted to double automatically. The result is 10.0, which is

printed as 10 (A).

test.sum(10.5, 10) -> This does not match any method exactly, but it matches two methods with

compatible types: sum(float a, float b) and sum(double a, double b). The latter is more specific, as

double is closer to the argument types than float. The result is 20.5, which is printed as 20 (D).

Therefore, the output is B A D. Reference:

Oracle Certified Professional: Java SE 17 Developer

Java SE 17 Developer

OCP Oracle Certified Professional Java SE 17 Developer Study Guide

Method Overloading in Java

Type conversion in Java with Examples

Java Method Overloading with automatic type conversions

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)