Assuming that the serializeBanana2() and the deserializeBanana2() methods will correctly use Java serialization and given:
import java.io.*;
class Food {Food() { System.out.print(”1”); } }
class Fruit extends Food implements Serializable {
Fruit() { System.out.print(”2”); } }
public class Banana2 extends Fruit { int size = 42;
public static void main(String [] args) {
Banana2 b = new Banana2();
b.serializeBanana2(b); // assume correct serialization
b = b.deserializeBanana2(b); // assume correct
System.out.println(” restored “+ b.size + “ “); }
// more Banana2 methods
}
What is the result?()
A. Compilation fails.
B. 1 restored 42
C. 12 restored 42
D. 121 restored 42
E. 1212 restored 42
F. An exception is thrown at runtime.
您可能感兴趣的试卷
你可能感兴趣的试题
Assuming that the serializeBanana() and the deserializeBanana() methods will correctly use Java serialization and given:
import java.io.*;
class Food implemertts Serializable {int good = 3;}
class Fruit externds Food {int juice = 5;}
public class Banana extends Fruit {
int yellow = 4;
public static void main(String [] args) {
Banana b = new Banana(); Banana b2 = new Banana();
b.serializeBanana(b); // assume correct serialization
b2 = b.deserializeBanana(); // assume correct
System.out.println(”restore “+b2.yellow+ b2.juice+b2.good);
}
// more Banana methods go here
}
What is the result?()
A. restore 400
B. restore 403
C. restore 453
D. Compilation fails.
E. An exception is thrown at runtime.
A. Objects from classes that use aggregation cannot be serialized.
B. Art object serialized on one JVM can be successfully deserialized on a different JVM.
C. The values in fields with the volatile modifier will NOT survive serialization anddeserialization.
D. The values in fields with the transient modifier will NOT survive serialization anddeserialization.
E. It is legal to serialize an object of a type that has a supertype that does NOT implement java.io.Serializable.
1. import java.io.*;
2. public class Foo implements Serializable {
3. public int x, y;
4. public Foo( int x, int y) { this.x = x; this.y = y; }
5.
6. private void writeObject( ObjectOutputStream s)
7. throws IOException {
8. s.writeInt(x); s.writeInt(y)
9. }
10.
11. private void readObject( ObjectInputStream s)
12. throws IOException, ClassNotFoundException {
13.
14. // insert code here
15.
16. }
17. }
Which code, inserted at line 14, will allow this class to correctly serialize and deserialize?()
A. s.defaultReadObject();
B. this = s.defaultReadObject();
C. y = s.readInt(); x = s.readInt();
D. x = s.readInt(); y = s.readInt();
import java.io.*;
public class Forest implements Serializable {
private Tree tree = new Tree();
public static void main(String [] args) {
Forest f= new Forest();
try {
FileOutputStream fs = new FileOutputStream(”Forest.ser”);
ObjectOutputStream os = new ObjectOutputStream(fs);
os.writeObject(f); os.close();
} catch (Exception ex) { ex.printStackTrace(); }
}
}
class Tree { }
What is the result?()
A. Compilation fails.
B. An exception is thrown at runtime.
C. An instance of Forest is serialized.
D. A instance of Forest and an instance of Tree are both serialized.
A. closing the stream
B. flushing the stream
C. writing to the stream
D. marking a location in the stream
E. writing a line separator to the stream
10. class MakeFile {
11. public static void main(String[] args) {
12. try {
13. File directory = new File(”d”);
14. File file = new File(directory,”f”);
15. if(!file.exists()) {
16. file.createNewFile();
17. }
18. } catch (IOException e) {
19. e.printStackTrace
20. }
21. }
22. }
The current directory does NOT contain a directory named “d.” Which three are true?()
A. Line 16 is never executed.
B. An exception is thrown at runtime.
C. Line 13 creates a File object named “d”.
D. Line 14 creates a File object named “f‟.
E. Line 13 creates a directory named “d” in the file system.
F. Line 16 creates a directory named “d” and a file “f” within it in the file system.
G. Line 14 creates a file named "f " inside of the directory named “d” in the file system.
public class Wow {
public static void go(short n) {System.out.println(”short”); }
public static void go(Short n) {System.out.println(”SHORT”);}
public static void go(Long n) {System.out.println(” LONG”); }
public static void main(String [] args) {
Short y= 6;
int z=7;
go(y);
go(z);
}
}
What is the result?()
A. short LONG
B. SHORT LONG
C. Compilation fails.
D. An exception is thrown at runtime.
public class Yikes {
public static void go(Long n) {System.out.println(”Long “);}
public static void go(Short n) {System.out.println(”Short “);}
public static void go(int n) {System.out.println(”int “);}
public static void main(String [] args) {
short y= 6;
long z= 7;
go(y);
go(z);
}
}
What is the result?()
A. int Long
B. Short Long
C. Compilation fails.
D. An exception is thrown at runtime.
public class TestString3 {
public static void main(String[] args) {
// insert code here
System.out.println(s);
}
}
Which two code fragments, inserted independently at line 3, generate the output 4247?()
A. String s = “123456789”; s = (s-”123”).replace(1,3,”24”) - “89”;
B. StringBuffer s = new StringBuffer(”123456789”); s.delete(0,3).replace( 1,3, “24”).delete(4,6);
C. StringBuffer s = new StringBuffer(”123456789”); s.substring(3,6).delete( 1 ,3).insert(1, “24”);
D. StringBuilder s = new StringBuilder(”123456789”); s.substring(3,6).delete( 1 ,2).insert( 1, “24”);
E. StringBuilder s = new StringBuilder(”123456789”); s.delete(0,3).delete( 1 ,3).delete(2,5).insert( 1, “24”);
public String makinStrings() {
String s = “Fred”;
s = s + “47”;
s = s.substring(2, 5);
s = s.toUpperCase();
return s.toString();
}
How many String objects will be created when this method is invoked?()
A. 1
B. 2
C. 3
D. 4
E. 5
F. 6
最新试题
A programmer must create a generic class MinMax and the type parameter of MinMax must implement Comparable. Which implementation of MinMax will compile?()
Which two statements are true?()
What is the appropriate definition of the hashCode method in class Person?()
Which two of statements are true?()
What is the output if the main() method is run?()
What is the result?()
Which two are possible results?()
What is the result?()
Which statement is true?()
Given: foo and bar are public references available to many other threads, foo refers to a Thread and bar is an Object. The thread foo is currently executing bar.wait(). From another thread, what provides the most reliable way to ensure that foo will stop executing wait()?()