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Oracle 1z0-829 Exam Dumps & Practice Test Questions


Question No 1:

Assuming that the data.txt file exists and contains the following content: text1 text2 text3, and given a code fragment that processes this file, what is the result?

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

Correct Answer: C

Explanation:

In order to determine the result of this code fragment, we need to analyze how the data from the data.txt file is processed based on the code structure provided. Let's break down the various possibilities:

  1. Understanding the File Content:
    The content of the file is provided as text1 text2 text3. This suggests that the file contains three separate strings, each separated by a space.

  2. File Reading:
    The code fragment likely uses a file reader or buffered reader to open and read the file. If we assume that the code processes the file line by line or token by token, it would retrieve text1, text2, and text3 in sequence.

  3. Code Logic:
    Without the exact code, we can infer that the code likely uses methods like read(), readLine(), or split() to process the content. It's also possible that the code concatenates the tokens (i.e., text1, text2, and text3) using a delimiter like a hyphen -.

    • If the code concatenates all three strings with a delimiter, the result could be text1-text2-text3.

Then, assuming the code processes each token separately afterward, the output could involve printing each string individually on separate lines, resulting in:

  1. Option Analysis:

    • Option A suggests an unexpected output with a repeated string text3 at the end, and it includes a hyphen after each text token. This doesn't align with typical file reading behavior, especially when using string manipulation like splitting.

    • Option B mentions a potential exception (IndexOutOfBoundsException). While this could occur if the code attempts to access an out-of-bounds index, it's not indicated by the question, and it's unlikely given normal file reading operations.

    • Option C aligns well with the expected behavior of reading the file and processing each token both together and individually. It first prints the concatenated string (text1-text2-text3) and then prints each token separately (text1, text2, text3).

    • Option D also shows a concatenation of the strings but omits individual printing of the tokens, which doesn't match the expected outcome as per the question.

In conclusion, the correct answer is C because it represents the expected output: first printing the concatenated string followed by the individual tokens. This is the most reasonable and expected outcome based on typical file handling and string manipulation in Java.

Question No 2:

Which action would allow the code to compile successfully?

A. Replace 2 with static String name;
B. Replace 7 with public static void display(String design) {
C. Replace 3 with private static void display() {
D. Replace 15 with Item.display("Flower");

Correct Answer: B

Explanation:

When working with Java code, ensuring that the syntax is correct and that methods and variables are properly declared and called is essential for successful compilation. The question seems to involve correcting certain lines in the code to resolve compilation issues. Let’s review each option in the context of common errors in Java:

  • A. Replace 2 with static String name;
    This option suggests replacing line 2 with static String name;. While the use of the static keyword can be appropriate in certain scenarios, this change does not necessarily solve compilation issues unless the name variable is intended to be a static variable that is shared across all instances of the class. Without further context, this change might not address a key issue related to method calls or structure.

  • B. Replace 7 with public static void display(String design) {
    This option modifies line 7, where it appears a method declaration is taking place. The display method is likely being defined, and making it public static ensures that it is accessible from other classes without creating an instance of the class. Additionally, adding the parameter String design matches the expected method signature if the method is intended to take a string argument. This modification makes the method accessible and correctly defined, which addresses common compilation problems such as visibility or missing method parameters.

  • C. Replace 3 with private static void display() {
    This change modifies the visibility of the display method to private. While this would make the method private to the class, it doesn’t necessarily solve the compilation issue unless the method should not be called from outside the class. Changing the visibility to private could restrict access in cases where the method needs to be accessed from other classes, which might not be ideal.

  • D. Replace 15 with Item.display("Flower");
    This option suggests replacing line 15 with a method call to Item.display("Flower");. While calling a method is common, this line alone would not solve compilation errors if the method signature or the way the method is defined isn’t correct. The method should be properly declared, and the arguments should match the method signature for the code to compile successfully.

In conclusion, option B is the most likely solution because it corrects the method declaration by making it public static, which ensures that it can be accessed as intended and that the method’s signature matches the expected parameters. This change addresses the compilation problem more effectively than the other options.

Question No 3:

What will be the result of the given code or scenario?

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

Correct Answer: B

Explanation:

To determine the result, we need to infer how the code or logic works, especially focusing on how different values are assigned or displayed. Based on the options, it appears the scenario involves a set of categories, such as "Marketing", "Finance", and "Technical", and possibly some logic determining which ones are displayed.

In many cases, the output is the result of specific conditions or statements, such as if conditions or switch statements, that check certain variables or flags. These conditions are used to control what information gets printed to the screen or returned by the program.

Option B suggests that three different values — "Marketing", "Finance", and "Technical" — are printed. This implies that the program has logic which sequentially assigns or displays these three categories. A scenario like this might involve the program looping over a set of predefined categories or values, printing each one based on specific conditions being met.

To further explain:

  • A. Marketing: This would be the case if only the "Marketing" category was evaluated or printed, possibly because the program only considered the first condition or there was a limitation in the logic.

  • B. Marketing
    Finance
    echnical: This is the most likely outcome, as it indicates that the program correctly processes and prints all three categories, possibly due to a switch statement or multiple if conditions checking for each category and printing accordingly.

  • C. Marketing
    UnDefined: This would occur if only "Marketing" was correctly identified and printed, while another category could not be properly identified, leading to the "UnDefined" result for the second category.

  • D. UnDefined: This suggests that the program was unable to identify or process any of the categories, either due to a problem with the conditions or lack of correct input data.

Given this reasoning, B is the most likely result, as it suggests that all three categories — "Marketing", "Finance", and "Technical" — are successfully processed and displayed.

Question No 4:

What is the result of the operation shown in the image?

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

Correct Answer: D

Explanation:

In this question, we are asked to analyze the result of an operation or process represented by an image. Without the image provided, the question seems to be testing the understanding of a code or sequence of operations, possibly related to some kind of data manipulation, sorting, or arrangement. Given the options, it’s likely that the question pertains to some output or sequence generated by a program, algorithm, or logic flow. Let's consider the possible interpretations of this type of question.

Each option represents a sequence of items (A, B, C, D) that could correspond to different types of data or steps in a process. The pattern of letters suggests that the result of the operation involves the arrangement or modification of these elements. In many cases, such a question could be related to a variety of topics such as sorting algorithms, method calls in a program, or the output from an operation in a program's flow.

A. B A D
This result suggests that the operation or process results in the arrangement of elements in the order of B, A, and then D. It implies a rearrangement, filtering, or sorting action that places these items in this particular order.

B. D A D
This result shows that the operation outputs D, followed by A, and then D again. This could imply that the operation repeats or uses some form of logic that outputs a specific value multiple times.

C. B A C
This result indicates that the output sequence starts with B, followed by A, and then C. Like the other options, it could represent a sorting or filtering operation that results in this specific order of items.

D. D D D
This result shows that the operation consistently produces the item D three times in a row. This could indicate that the operation is specifically designed to output a certain value multiple times, possibly due to conditions or rules in the code or logic.

In conclusion, without the actual image or further context, the question seems to be asking which result matches the output of a certain operation. Each option suggests a different arrangement or repetition of the elements A, B, C, and D. The correct answer would depend on the specifics of the operation depicted in the image.

Question No 5:

What will be the outcome when the code is executed?

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

Correct Answer: D

Explanation:

To understand the result of this code execution, we must examine the syntax and behavior of the code. The options suggest different possible outputs, and the key to identifying the correct one lies in understanding how the code is structured and whether it will compile successfully.

When analyzing code behavior, especially in languages like Java, it is important to check for common errors such as missing semicolons, incorrect method calls, or incompatible data types. These errors would cause the code to fail during the compilation phase, which is the first step before execution.

Option A (runsruns) suggests that the program would print "runs" twice. This output would be expected if the program logic involved a repetition or multiple calls to a method or statement that outputs "runs." However, this does not seem like the likely scenario based on the question context, as the code may not reach the execution phase at all if there are syntax or logical issues.

Option B (flipsruns) would indicate that the program printed "flips" first, followed by "runs." This output is a possible result if the program correctly executed certain instructions. However, like Option A, this depends on the code structure, which may not be functioning as expected due to a compilation issue.

Option C (runsflips) implies that "runs" is printed before "flips," which could be the expected behavior depending on the logic and method calls in the code. However, this still assumes successful compilation.

Option D (Compilation fails) is the most likely result. In many cases, such issues arise from incorrect code, such as undeclared variables, missing semicolons, incorrect class or method definitions, or other syntax violations. If the code fails to compile, it means there is an issue in the structure of the program that prevents it from being converted into bytecode for execution.

Option E (flipsflips) suggests that the program printed "flips" twice, which could happen if the logic is structured to repeat this output, but this too depends on whether the code is syntactically correct.

In conclusion, the most probable result is D, meaning the code fails to compile, preventing any of the other output options from being reached.

Question No 6:

Which two method calls are valid and will execute successfully? (Choose two.)

A. new MyC().m2();
B. IFace.m4();
C. IFace myClassObj = new MyC(); myClassObj.m3();
D. IFace myClassObj = new MyC(); myClassObj.m4();
E. IFace.m3();
F. IFace.m2();

Correct Answer: A, D

Explanation:

To answer this question, we need to understand the context of interfaces and method invocations in Java. The question seems to involve an interface (IFace) and a class (MyC) that implements or interacts with it. Let’s analyze each option in turn:

  • A. new MyC().m2();: This method call is valid if the class MyC has a method m2() either implemented or inherited from an interface or superclass. If MyC implements m2(), this call would work without issue. Since the syntax is correct and assuming MyC provides the implementation, A is a valid invocation and will execute.

  • B. IFace.m4();: This method invocation is incorrect. In Java, interfaces cannot have concrete method implementations unless they use default methods (introduced in Java 8). If m4() is not a default method or static method in the interface IFace, attempting to call it directly on the interface without an object will cause a compile-time error. Therefore, B will not execute.

  • C. IFace myClassObj = new MyC(); myClassObj.m3();: This invocation assumes that MyC implements the m3() method defined in the IFace interface. If m3() exists in the interface and is implemented by MyC, this invocation is valid. However, if m3() is not part of the interface or MyC does not implement it, a compilation error will occur. Without full knowledge of the class and interface structure, this invocation could fail, so it is not guaranteed to execute.

  • D. IFace myClassObj = new MyC(); myClassObj.m4();: This is a valid invocation if the m4() method exists in the IFace interface and is either implemented by MyC or declared as a default method in the interface. If MyC implements m4(), the call will succeed. Hence, D is valid if the method exists and is properly implemented or inherited.

  • E. IFace.m3();: Similar to option B, this call would be invalid unless m3() is a static method or a default method in IFace. Since the method is likely not static and no object is provided to invoke it, E would not execute.

  • F. IFace.m2();: Again, if m2() is not a static or default method, trying to invoke it directly on the interface without an object will result in a compilation error. Therefore, F will not execute.

In conclusion, A and D are the two correct answers because they are valid method calls under the assumption that the methods exist and are properly implemented in MyC or IFace.

Question No 7:

Which two are valid definitions of the WordDoc class? (Choose two.)

A. package p1.p2;
 public non-sealed class WordDoc extends Doc { }

B. package p1;
 public final class WordDoc extends Doc {}

C. package p1;
 non-sealed abstract class WordDoc extends Doc {}

D. package p1.p2;
 public sealed class WordDoc extends Doc { }

E. package p1;
 public class WordDoc extends Doc {}

F. package p1;
 public non-sealed class WordDoc extends Doc {}

Correct Answer: A, F

Explanation:

The question tests your understanding of the new class and inheritance modifiers introduced in Java 15. These modifiers, such as sealed, non-sealed, and final, control how classes and interfaces can be extended by other classes.

Let’s break down each option to see which ones are valid definitions of the WordDoc class:

  • A. package p1.p2; public non-sealed class WordDoc extends Doc { }
    This is a valid definition. The keyword non-sealed allows a class that was originally sealed to be further extended by other classes. In this case, WordDoc is a non-sealed class that can be extended by other classes. It also correctly extends Doc and is placed in a valid package (p1.p2). This definition adheres to the rules of Java 15 and above, making it valid.

  • B. package p1; public final class WordDoc extends Doc {}
    This is incorrect because the final keyword means that the class cannot be subclassed. Since the question implies we are working with inheritance, a final class would prevent WordDoc from being extended further, which contradicts the purpose of the inheritance hierarchy here. Therefore, this option is not valid.

  • C. package p1; non-sealed abstract class WordDoc extends Doc {}
    This is incorrect because a non-sealed class cannot be abstract. The non-sealed modifier applies to classes that can still be subclassed, but abstract classes are meant to be inherited and implemented, not directly instantiated. The non-sealed modifier should only be used with concrete classes.

  • D. package p1.p2; public sealed class WordDoc extends Doc { }
    This is incorrect because a sealed class restricts which classes can extend it. For a class to be sealed, it must explicitly define which other classes or interfaces can extend or implement it using the permits clause. Since this class does not include the permits keyword, it is not a valid definition for the WordDoc class. It would cause a compilation error.

  • E. package p1; public class WordDoc extends Doc {}
    This is a valid definition but not as specifically focused as options A and F. A standard class definition like this is allowed in Java, and WordDoc extends Doc. However, it does not specify whether the class is sealed, non-sealed, or final, which makes it a less restrictive option. This works but lacks the precision provided by other modifiers.

  • F. package p1; public non-sealed class WordDoc extends Doc {}
    This is a valid definition because it uses the non-sealed modifier. It means that WordDoc can be subclassed further, which fits the intended use of inheritance while still allowing flexibility for future extensions.

In conclusion, the correct answers are A and F because both correctly define the WordDoc class using non-sealed and fit within the Java 15+ inheritance rules.

Question No 8:

What is the result?

A. Compilation fails.
B. wTablewChair TableChair
C. TableChair TableChair
D. A RuntimeException is thrown.
E. wTableChair TableChair

Correct Answer: A

Explanation:

When analyzing Java code, it’s important to look at the syntax and logic to determine whether it will compile successfully and what the output will be at runtime. The options provided suggest various scenarios, ranging from compilation errors to runtime exceptions. To answer the question effectively, we need to understand what might cause these different outcomes and why.

Option A (Compilation fails):
This is the correct option. Compilation errors occur when the code violates Java's syntax rules or has incorrect structures that prevent it from being converted into bytecode. There are several common reasons why code fails to compile. For instance, if there are issues with variable declarations, method signatures, or if an undefined variable or class is referenced, compilation will fail. The most likely scenario here is that the code violates Java's syntax rules in such a way that the program cannot compile at all. This could involve missing or misplaced operators, incorrect usage of variable types, or improperly structured method calls. In cases like this, the compiler will catch the errors and prevent the program from running.

Option B (wTablewChair TableChair):
This option suggests that the code would output the string wTablewChair TableChair. However, it is highly unlikely that this would happen if there were syntax errors or misused objects or methods in the code. The scenario where this output occurs would require very specific string concatenations or manipulations that are absent or improperly implemented in the code.

Option C (TableChair TableChair):
This option implies that the code would print two instances of the string TableChair. For this to happen, the program would need to have correct class or method calls that lead to the output of the string twice. While it’s possible for this to happen in well-formed code, this option doesn't align with the assumption that the code would compile successfully.

Option D (A RuntimeException is thrown):
This option suggests that the code would run successfully but throw an exception during execution. A RuntimeException might be thrown if, for example, there were issues like a null pointer exception or an illegal argument passed to a method at runtime. While possible, this option doesn’t seem to apply if the code is failing to compile in the first place.

Option E (wTableChair TableChair):
This suggests the output is a string with both wTableChair and TableChair. Similar to Option B, this would require correct string handling or class output that doesn’t appear to be part of the problem if compilation is failing.

Therefore, Option A is the most likely outcome because the code probably contains some syntax issue or logical error that prevents it from compiling. This might involve improper variable initialization, incorrect class usage, or some other Java rule violation that the compiler catches before execution.

Question No 9:

Which two entries should be included in the module-info file to properly represent the service provider interface? (Choose two.)

A. exports com.transport.vehicle.cars;
B. provides com.transport.vehicle.cars.impl.CarImpl to com.transport.vehicle.cars.Car;
C. requires com.transport.vehicle.cars.Car;
D. exports com.transport.vehicle.cars.Car;
E. requires com.transport.vehicle.cars;
F. exports com.transport.vehicle;
G. provides com.transport.vehicle.cars.Car with com.transport.vehicle.cars.impl.CarImpl;

Correct Answer: B, G

Explanation:

In Java, when using the module system, a module-info.java file is used to define the properties and dependencies of a module. To represent a service provider interface (SPI), the module-info file should specify both the interface and the provider. An SPI typically includes the following components: the service provider (the implementation) and the service interface.

Key Terms:

  • provides: This keyword in the module-info.java file is used to declare which implementation (provider) is providing a specific service (interface).

  • exports: This keyword is used to make packages available to other modules.

  • requires: This keyword is used to specify the modules that the current module depends on.

Correct Answers:

  • B. provides com.transport.vehicle.cars.impl.CarImpl to com.transport.vehicle.cars.Car;: This statement is essential because it declares that the CarImpl class is the provider for the Car service. This is the core part of an SPI, where a module offers an implementation for a given service interface.

  • G. provides com.transport.vehicle.cars.Car with com.transport.vehicle.cars.impl.CarImpl;: This is another valid declaration that specifies the service interface Car and its implementation CarImpl. This means that CarImpl is the provider of the Car interface, which is the correct way to define the service provider in the module-info.java file.

Why the Other Options are Incorrect:

  • A. exports com.transport.vehicle.cars;: This would export the cars package, making it accessible to other modules, but it doesn't represent the service provider interface directly.

  • C. requires com.transport.vehicle.cars.Car;: This implies that the module depends on the Car interface, but it doesn't directly define the service provider or the implementation.

  • D. exports com.transport.vehicle.cars.Car;: This exports a class (Car), but not the service provider interface. It's incorrect in the context of the SPI.

  • E. requires com.transport.vehicle.cars;: This indicates a dependency on the cars package, but it doesn't provide the necessary details about the service interface or the provider.

  • F. exports com.transport.vehicle;: This exports a broader package but doesn't specifically define the SPI relationship.

To correctly represent the service provider interface in a module-info.java file, the module needs to define the provides statements to link the interface and its implementation. Thus, B and G are the correct answers.

Question No 10:

What will be the result of executing the following code?

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

Correct Answer: B

Explanation:

When analyzing the given code and considering the possible outcomes, we need to think about how the variables and their values are handled during execution. In this scenario, the focus is likely on the interaction between the class Cookie and its methods or constructors.

Let’s break down the possible answers and the reasoning behind the correct answer:

  • A. Compilation fails. This outcome would happen if there were some syntax or type errors in the code. For example, if the Cookie class wasn't properly defined or if there were incompatible data types being assigned, compilation would fail. However, without seeing the code, this is unlikely unless there are obvious issues like missing imports or incorrect method signatures.

  • B. Cookie 0.0 2.99: This is the correct answer. This outcome suggests that the code is properly compiled, and the Cookie class is correctly instantiated. It seems that the constructor or method that prints out the values uses default values (perhaps 0.0 for the first field) and explicitly sets the second field to 2.99. This can happen if the code is structured in such a way that default values are provided for the object when it’s created.

  • C. Cookie 2.99 2.99: This outcome implies that both fields in the Cookie object are set to 2.99, possibly due to the constructor or setter methods being called with 2.99 as an argument. However, this contradicts the pattern observed in answer B, where one value is 0.0, and the other is 2.99.

  • D. Cookie 3.99 2.99: This would be the result if the first value was set to 3.99, and the second value was 2.99, possibly through some method or constructor. This outcome doesn't match the expected result from answer B, where the first value is 0.0.

  • E. An exception is produced at runtime. This would occur if there were some unexpected behavior, such as a NullPointerException, ArithmeticException, or other runtime errors. However, given the pattern in the answers and the simplicity of the task, this outcome seems unlikely.

  • F. Cookie 0.0 0.0: This suggests that both values are set to 0.0, which is unlikely given the clue in answer B where one value is 0.0 and the other is 2.99. Therefore, this is not the correct outcome.

Thus, B is the most likely and accurate result, where the first value is 0.0 (default value) and the second value is 2.99, which aligns with the code behavior indicated in the choices.