Free Oracle 1z0-829 Exam Dumps Questions

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

What is the result?

Correct Answer:D
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

Given the code fragment:

What is the result?

Correct Answer:B
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. 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/17/docs/api/java.base/java/time/Instant.html#truncatedTo(java.time.temporal.TemporalUnit)

Which statement is true about migration?

Correct Answer:B
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

Given:

What is the result?
A.
1001
1001
1000
B.
101
101
1000
C.
100
100
1000
D.
1001
100
1000

Correct Answer:D
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.

Given:

What is the result?

Correct Answer:C
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

Given:

What is the result?

Correct Answer:B
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.