Oracle 1Z0-829 Exam Dumps

The answer is E because the code fragment creates a new Pet object with the name ''Dog'' and assigns it to the variable p. Then, it assigns p to p1. Next, it changes the name of p1 to ''Cat''. Then, it assigns p1 to p. Finally, it sets p to null and prints the name of p and p1. The output will be ''Cat'' and ''null'' because p is set to null and p1 still points to the Pet object with the name ''Cat''.

The code fragment is comparing the values of a, b, and c using the < and > operators. The first comparison, d, is checking if a is less than b and greater than c. Since a is equal to 2, b is equal to -2, and c is equal to -4, this comparison will evaluate to true. The second comparison, e, is checking if a is greater than b and a is greater than c. Since a is equal to 2, b is equal to -2, and c is equal to -4, this comparison will evaluate to false. Therefore, the result will be true 1 false 2.Reference:Operators (The Java Tutorials > Learning the Java Language - 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 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.

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.Reference:

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