JAVA Development Engineer Written Exam Questions (AI Volume)
Writing requirements: 1. The duration is 50 minutes; 2. Internet access is prohibited during the written test; 3. Mutual plagiarism is prohibited
Written test start time: _______________________ Written test end time: _________________________
Candidate Name: ____________________ Written Test Score: ____________________
1. Multiple-choice questions (multiple-choice for some questions, a total of 17 questions, 2 points for each question, a total of 34 points)
1. In java, the way to achieve the effect of multiple inheritance is ()
A Internal Class B Adapter C Interface D Sync
2. Which of the following methods can be used to create a new thread is ()
A implements the java.lang.Runnable interface and overrides the start() method
B implements the java.lang.Runnable interface and overrides the run() method
C implements the java.lang.Thread interface and overrides the start() method
D implements the java.lang.Thread interface and overrides the run() method
3. After reading the following code, the correct statement is ()
public class Person{
int arr[] = new int[10];
public static void main(String args[]){
System.out.println(arr[i]);
}
}
A will generate an error when compiling
B compiles correctly, but will generate an error when run
C output zero
D output is empty
4. There are () that cannot be used to modify the interface
A private B public Cprotected D static
5. Which of the following statements is wrong ()
A can use this in a class method to call the class method of this class
B can be called directly when calling the class method of this class in the class method
C can only call class methods in this class from class methods
D must never call instance methods from within a class method
6. The result of running the following program is ()
String str1 =“hello”;
String str2 = "he"+new String("llo");
System.err.println(str1==str2);
A 0 B 1 C false D true
7. The running result of the following program: ()
public static void main(String args[]){
Thread t = new Thread(){
public void run(){
pong();
}
}
}
staic void pong(){
System.out.print("ping");
}
staic void pong(){
System.out.print("pong");
}
A pingpong B pongping C pingpong and pongping can both D do not output
8. Which of the following statements is correct ()
A LinkedList inherits from List
B AbstraSet inherits from Set
C HashSet inherits from AbstraSet
D WeakMap inherits from HashMap
9. The package that provides the ability of java to access the database is ()
A java.sql B java.awt C java.lang D java.swing
10. Which of the following are not keywords of java? ( )
A const B NULL C false D this E native
11. In jquery, if you want to remove all matching elements from the DOM, which of the following is correct? ( )
A delete() B empty() C remove() D removeAll()
12. Which of the following events is used to implement the remote httpget request loading information function in jquery?
A $.ajax() B load(url) C $.get(url) D $.getScript(url)
13. In jquery, if you want to hide an element, use ________ to achieve it, and display the hidden element with ______
14. Aggregate functions cannot be used in which of the following statements ()
A SELECT clause B HAVING clause C WHERE clause D Subquery E ORDER BY
15. The two related constraints of the table are ()
A Primary key and index B Foreign key and index C Primary key and foreign key D Internal key and foreign key
16. Use the SQL command to increase the value of the salary field in the teacher table by 500. The command that should be used is ()
A Replace salary with salary+500
B Update teacher salary with salary+500
C Update set salary with salary+500
D Update teacher set salary=salary+500
17. In Oracle, the following clause to limit the return value of the grouping function is ()
A WHERE B HAVING C ORDER BY D The return value of the grouping function cannot be limited
2. Questions and Answers (A total of 8 questions, a total of 66 points)
18. There are several ways of data in ajax? (6 points)
19. What is the difference between drop, deldte and truncate in the database? (6 points)
20. What is NaN and what is its type? How to test if a value is equal to NaN? (8 points)
21. What is a transaction and what are the four attributes of a transaction? (8 points)
22. What are the differences between Set and List? (8 points)
23. What is the difference between sleep() and wait()? (10 points)
24. What are the keywords of the facet of oracle and mysql databases? (10 points)
25. What is the difference between union all and union? (10 points)