[Jan 30, 2024] 1Z0-829 Exam Dumps - Oracle Practice Test Questions [Q25-Q49]

[Jan 30, 2024] 1Z0-829 Exam Dumps - Oracle Practice Test Questions

New Real 1Z0-829 Exam Dumps Questions

Oracle 1Z0-829 certification is an excellent way to validate your Java programming skills and enhance your career prospects. By earning this certification, you can demonstrate to potential employers that you have the knowledge and skills to develop Java applications using the latest technologies.

NEW QUESTION # 25
Assuming that the data, txt file exists and has the following content:
Text1
Text2
Text3
Given the code fragment:

What is the result?

A. text1-text2-text3
text3
B. text1-
text2-
text3-
text3
C. text1-text2-text3
text1
text2
text3
D. text1-text2-text3
A java.lang.indexoutofBoundsException is thrown.

Answer: A

Explanation:
Explanation
The answer is D because the code fragment reads the file "data.txt" and collects all the lines in the file into a single string, separated by hyphens. Then, it prints the resulting string. Next, it attempts to read the fourth line in the file (index 3) and print it. However, since the file only has three lines, an IndexOutOfBoundsException is thrown. References:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
Read contents of a file using Files class in Java

NEW QUESTION # 26
Given the course table:

Given the code fragment:

A. 0
B. true
C. 1
D. false

Answer: B

Explanation:
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)

NEW QUESTION # 27
Given:

What is the result?

A. 1 RAINY
B. Compilation fails
C. 0 CLOUDY
D. 0 Snowy
E. 1 Snowy

Answer: D

Explanation:
The code is defining an enum class called Forecast with three values: SUNNY, CLOUDY, and RAINY. The toString() method is overridden to always return "SNOWY". In the main method, the ordinal value of SUNNY is printed, which is 0, followed by the value of CLOUDY converted to uppercase, which is "CLOUDY". However, since the toString() method of Forecast returns "SNOWY" regardless of the actual value, the output will be "0 SNOWY". Reference: Enum (Java SE 17 & JDK 17), Enum.EnumDesc (Java SE 17 & JDK 17)

NEW QUESTION # 28
Which two code fragments compile?

Answer: A,C

Explanation:
The two code fragments that compile are B and E. These are the only ones that use the correct syntax for declaring and initializing a var variable. The var keyword is a reserved type name that allows the compiler to infer the type of the variable based on the initializer expression. However, the var variable must have an initializer, and the initializer must not be null or a lambda expression. Therefore, option A is invalid because it does not have an initializer, option C is invalid because it has a null initializer, and option D is invalid because it has a lambda expression as an initializer. Option B is valid because it has a String initializer, and option E is valid because it has an int initializer.
https://docs.oracle.com/en/java/javase/17/language/local-variable-type-inference.html

NEW QUESTION # 29
Given:

What is the result?

A. D D D
B. B A D
C. D A D
D. B A C

Answer: B

Explanation:
Explanation
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. References
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

NEW QUESTION # 30
Which two code fragments compile?

Answer: A,C

Explanation:
Explanation
The two code fragments that compile are B and E. These are the only ones that use the correct syntax for declaring and initializing a var variable. The var keyword is a reserved type name that allows the compiler to infer the type of the variable based on the initializer expression. However, the var variable must have an initializer, and the initializer must not be null or a lambda expression. Therefore, option A is invalid because it does not have an initializer, option C is invalid because it has a null initializer, and option D is invalid because it has a lambda expression as an initializer. Option B is valid because it has a String initializer, and option E is valid because it has an int initializer.
https://docs.oracle.com/en/java/javase/17/language/local-variable-type-inference.html

NEW QUESTION # 31
Given the code fragment:

Which action sorts the book list?

A. At Line n1, convert type to mutable array type.
B. At Line n2, replace books,sort() with books.stream().sort(0.
C. At Line n2, replace compareTo () with compare ().
D. At line n1, convert books type to mutable ArrayList type.

Answer: C

Explanation:
The code fragment is trying to sort a list of books using the Collections.sort() method. The correct answer is D, because the compareTo() method is not the correct way to compare two objects in a Comparator. The compare() method is the correct way to compare two objects in a Comparator and return an int value that indicates their order1. The compareTo() method is used to implement the Comparable interface, which defines the natural order of objects of a class2. The other options are incorrect because they either do not change the type of the list, which is already mutable, or they do not use the correct syntax for sorting a stream, which requires a terminal operation such as collect()3. Reference: Comparator (Java SE 17 & JDK 17), Comparable (Java SE 17 & JDK 17), Stream (Java SE 17 & JDK 17)

NEW QUESTION # 32
Given the code fragment:

Which two statements at Line nl independently enable you to print 1250?

A. Integer res = 250 + integer . valueof (s);
B. Integer res = 250 + s:
C. Integer res = 250;
D. Integer res = 250 + integer (s2):
E. Integer res= 250 + s2;
F. Integer res = 250 + integer.parseint (s)

Answer: A,F

Explanation:
Res = + s2;
Explanation:
The code fragment is creating a string variable "s" with the value "10_00" and an integer variable "s2" with the value 10. The string "s" is using an underscore as a separator for readability, which is allowed in Java SE 171. The question is asking for two statements that can add 250 to the numeric value of "s" and assign it to an integer variable "res". The correct answers are A and E because they use the methods parseInt and valueOf of the Integer class to convert the string "s" to an integer. Both methods interpret the string as a signed decimal integer and return the equivalent int or Integer value23. The other options are incorrect because they either use invalid syntax, such as B and C, or they do not convert the string "s" to an integer, such as D and F. Reference: Binary Literals (The Java™ Tutorials > Learning the Java Language > Numbers and Strings), Integer (Java SE 17 & JDK 17), Integer (Java SE 17 & JDK 17)

NEW QUESTION # 33
Given:

Which statement is true?

A. The program throws StockException.
B. The program throws outofStockException.
C. The program fails to compile.
D. The program throws ClassCastException

Answer: C

Explanation:
The answer is B because the code fragment contains a syntax error that prevents it from compiling. The code fragment tries to catch a StockException in line 10, but the catch block does not have a parameter of type StockException. The catch block should have a parameter of type StockException, such as:
catch (StockException e) { // handle the exception }
This is required by the Java syntax for the catch clause, which must have a parameter that is a subclass of Throwable. Without a parameter, the catch block is invalid and causes a compilation error.
Option A is incorrect because the program does not throw a StockException, as it does not compile.
Option C is incorrect because the program does not throw an OutofStockException, as it does not compile.
Option D is incorrect because the program does not throw a ClassCastException, as it does not compile. Reference:
Oracle Certified Professional: Java SE 17 Developer
Java SE 17 Developer
OCP Oracle Certified Professional Java SE 17 Developer Study Guide
The try-with-resources Statement (The Java™ Tutorials > Essential Classes > Exceptions) The catch Blocks (The Java™ Tutorials > Essential Classes > Exceptions)

NEW QUESTION # 34
Given:

What is the result?

A. Compilation fails
B. flipsflips
C. flipsruns
D. runsflips
E. runsruns

Answer: A

Explanation:
Explanation
The code fragment will fail to compile because the play method in the Dog class is declared as private, which means that it cannot be accessed from outside the class. The main method is trying to call the play method on a Dog object, which is not allowed. Therefore, the code fragment will produce a compilation error.

NEW QUESTION # 35
Given the code fragment:

Which code fragment invokes all callable objects in the workers set?

Answer: C

Explanation:
Explanation
The code fragment in Option C invokes all callable objects in the workers set by using the ExecutorService's invokeAll() method. This method takes a collection of Callable objects and returns a list of Future objects representing the results of the tasks. The other options are incorrect because they either use the wrong method (invokeAny() or submit()) or have syntax errors (missing parentheses or semicolons). References: AbstractExecutorService (Java SE 17 & JDK 17) - Oracle

NEW QUESTION # 36
Given the product class:

And the shop class:

What is the result?

A. Cookie 2.99 2.99
B. Compilation fails
C. Cookie 0.0 2.99
D. Cookie 3.99 2.99
E. An exception is produced at runtime
F. Cookie 0.0 0.0

Answer: B

Explanation:
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]

NEW QUESTION # 37
Given the code fragment:

Which code fragment returns different values?

A. int sum = listOfNumbers. parallelStream () reduce ({m, n) -> m +n) orElse (5) +5;
B. int sum = listOfNumbers. parallelStream () reduce (5, Integer:: sum) ;
C. int sum = listOfNumbers. Stream () reduce ( Integer:: sum) ; +5;
D. int sum = listOfNumbers. Stream () reduce (0, Integer:: sum) + 5
E. int sum = listOfNumbers. Stream () reduce (5, (a, b) -> a + b) ;

Answer: C

Explanation:
Explanation
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. References 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()

NEW QUESTION # 38
Given:

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

Answer: B

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. Reference: Integer (Java SE 17 & JDK 17) - Oracle

NEW QUESTION # 39
Given the code fragment:

A. True:false:true:false
B. True:true:false:false
C. True:false:false:false
D. True:false:true:true

Answer: C

Explanation:
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 references, 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.

NEW QUESTION # 40
Given:

What is the result?

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

Answer: D

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.

NEW QUESTION # 41
Given the code fragments:

Which is true?

A. The program prints t1 : 1 : t2: 1 : t1 : 2 : t2: 2:
B. The program prints an exception
C. The program prints t1 : 1: t2 : 1: t1 : 1 : t2 : 1 : indefinitely
D. The program prints t1 : 1: t2 : 1: t1 : t2 : 2 : in random order.

Answer: A

Explanation:
Explanation
The code creates two threads, t1 and t2, and starts them. The threads will print their names and the value of the Atomic Integer object, x, which is initially set to 1. The threads will then increment the value of x and print their names and the new value of x. Since the threads are started at the same time, the output will be in random order. However, the final output will always be t1 : 1 : t2: 1 : t1 : 2 : t2: 2: References: AtomicInteger (Java SE
17 & JDK 17) - Oracle

NEW QUESTION # 42
Given the course table:

Given the code fragment:

A. 0
B. true
C. 1
D. false

Answer: B

Explanation:
Explanation
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. References: 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.Str

NEW QUESTION # 43
Given:

What is the result?

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

Answer: A

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". Reference: Pattern Matching for instanceof - Oracle Help Center

NEW QUESTION # 44
Given the code fragment:

Which two statements at Line nl independently enable you to print 1250?

A. Integer res = 250 + integer . valueof (s);
B. Integer res = 250 + s:
C. Integer res = 250 + integer (s2):
D. Integer res= 250 + s2;
E. Integer res = 250 + integer.parseint (s)
F. Integer res = 250; Res = + s2;

Answer: A,E

Explanation:
Explanation
The code fragment is creating a string variable "s" with the value "10_00" and an integer variable "s2" with the value 10. The string "s" is using an underscore as a separator for readability, which is allowed in Java SE
171. The question is asking for two statements that can add 250 to the numeric value of "s" and assign it to an integer variable "res". The correct answers are A and E because they use the methods parseInt and valueOf of the Integer class to convert the string "s" to an integer. Both methods interpret the string as a signed decimal integer and return the equivalent int or Integer value23. The other options are incorrect because they either use invalid syntax, such as B and C, or they do not convert the string "s" to an integer, such as D and F: References: Binary Literals (The Java™ Tutorials > Learning the Java Language > Numbers and Strings), Integer (Java SE 17 & JDK 17), Integer (Java SE 17 & JDK 17)

NEW QUESTION # 45
Which statement is true?

A. After the timed wait expires, the waited thread moves to the terminated state.
B. thread in waiting state consumes CPU cycles.
C. IllegalStateException is thrown if a thread in waiting state is moved back to runnable.
D. A thread in waiting state must handle InterrupedException.

Answer: D

Explanation:
Explanation
A thread in waiting state is waiting for another thread to perform a particular action, such as calling notify() or notifyAll() on a shared object, or terminating a joined thread. A thread in waiting state can be interrupted by another thread, which will cause the waiting thread to throw an InterruptedException and return to the runnable state. Therefore, a thread in waiting state must handle InterruptedException, either by catching it or declaring it in the throws clause. References: Thread.State (Java SE 17 & JDK 17), [Thread (Java SE 17 & JDK 17)]

NEW QUESTION # 46
Given:

What is the result

A. Marketing
Finance
Technical
B. Marketing
Undefined
C. Marketing
D. UnDefined

Answer: D

Explanation:
The code fragment is using the switch statement with the new Java 17 syntax. The switch statement checks the value of the variable desig and executes the corresponding case statement. In this case, the value of desig is "CTO", which does not match any of the case labels. Therefore, the default case statement is executed, which prints "Undefined". The other case statements are not executed, because there is no fall through in the new syntax. Therefore, the output of the code fragment is:
Undefined

NEW QUESTION # 47
Given the code fragment:

What is the result?

A. Logged out at: 2021-0112T21:58:19.880z
B. Logged out at: 2021-01-12T21:58:00z
C. A compilation error occurs at Line n1.
D. Can't logout

Answer: B

Explanation:
The code fragment is using the Java SE 17 API to get the current time and then truncating it to minutes. The result will be the current time truncated to minutes, which is why option B is correct. Reference:
https://education.oracle.com/products/trackp_OCPJSE17
https://mylearn.oracle.com/ou/learning-path/java-se-17-developer/99487
https://docs.oracle.com/javase/17/docs/api/java.base/java/time/Instant.html#truncatedTo(java.time.temporal.TemporalUnit)

NEW QUESTION # 48
Given the directory structure:

Given the definition of the Doc class:

Which two are valid definition of the wordDoc class?

A. Package p1;
Public non-sealed class wordDoc extends Doc ()
B. Package p1;
Public class wordDoc extends Doc ()
C. Package p1, p2;
Public non-sealed class WordDoc extends Doc ()
D. Package p1,
non-sealed abstract class WordDoc extends Doc ()
E. Package p1;
Public final class WordDoc extends Doc ()
F. Package p1, p2;
Public sealed class WordDoc extends Doc ()

Answer: A,E

Explanation:
The correct answer is A and F because the wordDoc class must be a non-sealed class or a final class to extend the sealed Doc class. Option B is incorrect because the wordDoc class must be non-sealed or final. Option C is incorrect because the wordDoc class cannot be in a different package than the Doc class. Option D is incorrect because the wordDoc class cannot be a sealed class. Option E is incorrect because the wordDoc class cannot be an abstract class. Reference: Oracle Certified Professional: Java SE 17 Developer, 3 Sealed Classes - Oracle Help Center

NEW QUESTION # 49
......

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[Jan 30, 2024] 1Z0-829 Exam Dumps - Oracle Practice Test Questions [Q25-Q49]

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