Oracle 1Z0-829 Dumps - Pass Java SE 17 Developer Exam in 2026

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 is using the stream methods allMatch, anyMatch, noneMatch, and findFirst on a list of strings called specialDays.These methods are used to perform matching operations on the elements of a stream, such as checking if all, any, or none of the elements satisfy a given predicate, or finding the first element that matches a predicate1. The predicate in this case is that the string equals ''Labour'' or ''Halloween''. The output will be:

False: because not all of the elements in specialDays are equal to ''Labour'' or ''Halloween''.

true: because at least one of the elements in specialDays is equal to ''Labour'' or ''Halloween''.

true: because none of the elements in specialDays are equal to both ''Labour'' and ''Halloween''.

Optional[NewYear]: because the first element in specialDays that matches the predicate is ''NewYear'', and the findFirst method returns an Optional object that may or may not contain a non-null value2.

The tryLock () method of the Lock interface is a non-blocking attempt to acquire a lock. It returns true if the lock is available and acquired by the current thread, and false otherwise. It does not wait for the lock to be released by another thread. This is different from the lock () method, which blocks the current thread until the lock is acquired, and does not return any value.Reference: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/concurrent/locks/Lock.html#tryLock(),3,4,5

The code will compile if the regNo variable is made public. This is because the regNo variable is being accessed in the main method of the App class, which is outside the scope of the Product class. Making the regNo variable public will allow it to be accessed from outside the class.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/tutorial/java/javaOO/accesscontrol.html

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)