Oracle 1z0-809 問題集

質問 1：
Given:
public class product {
int id; int price;
public Product (int id, int price) {
this.id = id;
this.price = price;
}
public String toString() { return id + ":" + price; }
}
and the code fragment:
List<Product> products = Arrays.asList(new Product(1, 10),
new Product (2, 30),
new Product (2, 30));
Product p = products.stream().reduce(new Product (4, 0), (p1, p2) -> {
p1.price+=p2.price;
return new Product (p1.id, p1.price);});
products.add(p);
products.stream().parallel()
.reduce((p1, p2) - > p1.price > p2.price ? p1 : p2)
.ifPresent(System.out: :println);
What is the result?
A. 2 : 30
B. The program prints nothing.
C. 4 : 0
D. 4 : 70
E. 4 : 602 : 303 : 201 : 10
正解：D

質問 2：
Given the records from the Employee table:

and given the code fragment:
try {
Connection conn = DriverManager.getConnection (URL, userName, passWord); Statement st = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); st.execute("SELECT*FROM Employee"); ResultSet rs = st.getResultSet(); while (rs.next()) { if (rs.getInt(1) ==112) { rs.updateString(2, "Jack");
}
}
rs.absolute(2);
System.out.println(rs.getInt(1) + " " + rs.getString(2));
} catch (SQLException ex) {
System.out.println("Exception is raised");
}
Assume that:
The required database driver is configured in the classpath.
The appropriate database accessible with the URL, userName, and passWord exists.
What is the result?
A. The Employee table is updated with the row:112 Jackand the program prints:112 Jack
B. The program prints Exception is raised.
C. The Employee table is updated with the row:112 Jackand the program prints:112 Jerry
D. The Employee table is not updated and the program prints:112 Jerry
正解：D

質問 3：
Given the code fragment:

What is the result?
A. The code reads the password without echoing characters on the console.
B. A compilation error occurs at line n2.
C. A compilation error occurs because the IOException isn't declared to be thrown or caught?
D. A compilation error occurs at line n1.
正解：D

質問 4：
Given:
class Book {
int id;
String name;
public Book (int id, String name) {
this.id = id;
this.name = name;
}
public boolean equals (Object obj) { //line n1
boolean output = false;
Book b = (Book) obj;
if (this.id = = b.id) {
output = true;
}
return output;
}
}
and the code fragment:
Book b1 = new Book (101, "Java Programing");
Book b2 = new Book (102, "Java Programing");
System.out.println (b1.equals(b2)); //line n2
Which statement is true?
A. A compilation error occurs. To ensure successful compilation, replace line n1 with:boolean equals (Book obj) {
B. A compilation error occurs. To ensure successful compilation, replace line n2 with:System.out.println (b1.equals((Object) b2));
C. The program prints true.
D. The program prints false.
正解：D

質問 5：
Given:
public class Customer {
private String fName;
private String lName;
private static int count;
public customer (String first, String last) {fName = first, lName = last;
++count;}
static { count = 0; }
public static int getCount() {return count; }
}
public class App {
public static void main (String [] args) {
Customer c1 = new Customer("Larry", "Smith");
Customer c2 = new Customer("Pedro", "Gonzales");
Customer c3 = new Customer("Penny", "Jones");
Customer c4 = new Customer("Lars", "Svenson");
c4 = null;
c3 = c2;
System.out.println (Customer.getCount());
}
}
What is the result?
A. 0
B. 2
C. 3
D. 4
E. 5
正解：D

質問 6：
Given the structure of the Student table:
Student (id INTEGER, name VARCHAR)
Given the records from the STUDENT table:

Given the code fragment:

Assume that:
What is the result?
A. The program prints Status: true and two records are deleted from the Student table.
B. The program prints Status: false and two records are deleted from the Student table.
C. A SQLException is thrown at runtime.
D. The program prints Status: false but the records from the Student table are not deleted.
正解：B

質問 7：
Given the code fragment:

Which modification enables the code to print Price 5 New Price 4?
A. Replace line n3 with .forEach (n -> System.out.println ("New Price" + n));
B. Replace line n2 with .map (n -> System.out.println ("New Price" + n -1)) and remove line n3
C. Replace line n2 with .mapToInt (n -> n - 1);
D. Replace line n1 with .forEach (e -> System.out.print ("Price" + e))
正解：A

質問 8：
Given:
class Worker extends Thread {
CyclicBarrier cb;
public Worker(CyclicBarrier cb) { this.cb = cb; }
public void run () {
try {
cb.await();
System.out.println("Worker...");
} catch (Exception ex) { }
}
}
class Master implements Runnable { //line n1
public void run () {
System.out.println("Master...");
}
}
and the code fragment:
Master master = new Master();
//line n2
Worker worker = new Worker(cb);
worker.start();
You have been asked to ensure that the run methods of both the Worker and Master classes are executed.
Which modification meets the requirement?
A. Replace line n1 with class Master extends Thread {
B. At line n2, insert CyclicBarrier cb = new CyclicBarrier(1, master);
C. At line n2, insert CyclicBarrier cb = new CyclicBarrier(2, master);
D. At line n2, insert CyclicBarrier cb = new CyclicBarrier(master);
正解：B

質問 9：
Given:

and the code fragment:

The threads t1 and t2 execute asynchronously and possibly prints ABCA or AACB.
You have been asked to modify the code to make the threads execute synchronously and prints ABC.
Which modification meets the requirement?
A. Replace line n1 with:private synchronized int count = 0;
B. start the threads t1 and t2 within a synchronized block.
C. Replace line n2 with:public synchronized void run () {
D. Replace line n2 with:volatile int count = 0;
正解：B