中文java技术网scjp考试题310-025(第二套3)51-91-147.htm

这是多次JAVA考试试题或模拟试题集锦

A. Compilation will fail.<br />
B. Compilation succeeds and no exceptions are thrown.<br />
C. Compilation succeeds but an exception is thrown at line 5 in ClassTest.java.<br />
D. Compilation succeeds but an exception is thrown at line 6 in ClassTest.java.<br />
Answer: B<br />
QUESTION NO: 77<br />
Given:<br />
1. public class ArrayTest {<br />
2. public static void main (String[]args) {<br />
3. float f1[], f2[];<br />
4. f1 = new float [10];<br />
5. f2 = f1;<br />
6. System.out.printIn (“f2[0]=” + f2[0]);<br />
7. }<br />
8. }<br />
What is the result?<br />
A. It prints f2[0] = 0.0<br />
B. It prints f2[0] = NaN<br />
C. An error at line 5 causes compile to fail.<br />
D. An error at line 6 causes compile to fail.<br />
E. An error at line 6 causes an exception at runtime.<br />
Answer: A<br />
QUESTION NO: 78<br />
Which two statements are true regarding the creation of a default constructor? (Choose Two)<br />
A. The default constructor initializes method variables.<br />
B. The compiler always creates a default constructor for every class.<br />
C. The default constructor invokes the no-parameter constructor of the superclass.<br />
D. The default constructor initializes the instance variables declared in the class.<br />
E. When a class has only constructors with parameters, the compiler does not create a default<br />
constructor.<br />
Answer: D, E<br />
QUESTION NO: 79<br />
Exhibit:<br />
1. class super {<br />
2. public int getLength() {return 4;}<br />
3. }<br />
4.<br />
5. public class Sub extends Super {<br />
6. public long getLength() {return 5;}<br />
7.<br />
8. public static void main (String[]args) {<br />
9. super sooper = new Super ();<br />
10. Sub sub = new Sub();<br />
11. System.out.printIn(<br />
12. sooper.getLength()+ “,” + sub.getLength() };<br />
13. }<br />
14. }<br />
What is the output?<br />
A. 4, 4<br />
B. 4, 5<br />
C. 5, 4<br />
D. 5, 5<br />
E. The code will not compile.<br />
Answer: E<br />
QUESTION NO: 80<br />
Given:<br />
1. public abstract class Test {<br />
2. public abstract void methodA();<br />
3.<br />
4. public abstract void methodB()<br />
5. {<br />
6. System.out.printIn(“Hello”);<br />
7. }<br />
8. }<br />
Which three changes (made independently) allow the code to compile? (Choose Three)<br />
A. Add a method body to methodA.<br />
B. Replace lines 5-7 with a semicolon (“.”)<br />
C. Remove the abstract qualifier from the declaration of Test.<br />
D. Remove the abstract qualifier from the declaration of methodB.<br />
E. Remove the abstract qualifier from the declaration of methodA.<br />
F. Remove methodB in its entirely and change class o interface in line 1.<br />
Answer: B, D, F<br />
<br />
QUESTION NO: 81<br />
Which determines if “prefs” is a directory and exists on the file system?<br />
A. Boolean exists=Directory.exists (“prefs”);<br />
B. Boolean exists=(new File(“prefs”)).isDir();<br />
C. Boolean exists=(new Directory(“prefs”)).exists();<br />
D. Boolean exists=(new File(“prefs”)).isDirectory();<br />
E. Boolean exists=true;<br />
Try{<br />
Directory d = new Directory(“prefs”);<br />
}<br />
catch (FileNotFoundException e) {<br />
exists = false;<br />
}<br />
Answer: D<br />
QUESTION NO: 82<br />
Which two create an InputStream and open file the “file.txt” for reading? (Choose Two)<br />
A. InputStream in=new FileReader(“file.txt”);<br />
B. InputStream in=new FileInputStream(“file.txt”);<br />
C. InputStream in=new InputStreamFileReader (“file.txt”, “read”);<br />
D. FileInputStream in=new FileReader(new File(“file.txt”));<br />
E. FileInputStream in=new FileInputStream(new File(“file.txt”));<br />
Answer: B, E<br />
QUESTION NO 83<br />
Which two construct an OutputSream that appends to the file “file.txt”? (Choose Two)<br />
A. OutputStream out=new FileOutputStream(“file.txt”);<br />
B. OutputStream out=new FileOutputStream(“file.txt”, “append”);<br />
C. FileOutputStream out=new FileOutputStream(“file.txt”, true);<br />
D. FileOutputStream out=new FileOutputStream(new file(“file.txt”));<br />
E. OutputStream out=new FileOutputStream(new File(“file.txt”)true);<br />
Answer: C, E<br />
<br />
QUESTION NO: 84<br />
Which constructs a BufferedIputStream?<br />
A. New BufferedInputStream(“in.txt”);<br />
B. New BufferedInputStream(new File(“in.txt”));<br />
C. New BufferedInputStream(new Writer(“in.txt”));<br />
D. New BufferedInputStream(new Writer(“in.txt”));<br />
E. New BufferedInputStream(new InputStream(“in.txt”));<br />
F. New BufferedInputStream(new FileInputStream(“in.txt”));<br />
Answer: F<br />
QUESTION NO: 85<br />
Which is a valid identifier?<br />
A. false<br />
B. default<br />
C. _object<br />
D. a-class<br />
Answer: C<br />
QUESTION NO: 86<br />
Exhibit:<br />
1. package foo;<br />
2.<br />
3. import java.util.Vector;<br />
4.<br />
5. private class MyVector extends Vector {<br />
6. int i = 1;<br />
7. public MyVector() {<br />
8. i = 2;<br />
9. }<br />
10. }<br />
11.<br />
12. public class MyNewVector extends MyVector {<br />
13. public MyNewVector () {<br />
14. i = 4;<br />
15. }<br />
16. public static void main (String args []) {<br />
17. MyVector v = new MyNewVector();<br />
18. }<br />
19. }<br />
The file MyNewVector.java is shown in the exhibit.<br />
What is the result?<br />
A. Compilation will succeed.<br />
B. Compilation will fail at line 5.<br />
C. Compilation will fail at line 6.<br />
D. Compilation will fail at line 14.<br />
E. Compilation will fail at line 17.<br />
Answer: B<br />
QUESTION NO: 87<br />
Given:<br />
1. public class Test {<br />
2. public static void main (String[]args) {<br />
3. String foo = args[1];<br />
4. String bar = args[2];<br />
5. String baz = args[3];<br />
6. System.out.printIn(“baz = ” + baz);<br />
7. }<br />
8. }<br />
And the output:<br />
Baz = 2<br />
Which command line invocation will produce the output?<br />
A. Java Test 2222<br />
B. Java Test 1 2 3 4<br />
C. Java Test 4 2 4 2<br />
D. Java Test 4 3 2 1<br />
Answer: C<br />
<br />
QUESTION NO: 88<br />
Given:<br />
8. int index = 1;<br />
9. String [] test = new String[3];<br />
10. String foo = test[index];<br />
What is the result?<br />
E. Foo has the value “”<br />
B. Foo has the value null<br />
C. An exception is thrown<br />
D. The code will not compile<br />
Answer: B<br />
QUESTION NO: 89<br />
Given:<br />
1. public interface Foo{<br />
2. int k = 4;<br />
3. }<br />
Which three are equivalent to line 2? (Choose Three)<br />
A. Final int k = 4;<br />
B. Public int k = 4;<br />
C. Static int k = 4;<br />
D. Private int k = 4;<br />
E. Abstract int k = 4;<br />
F. Volatile int k = 4;<br />
G. Transient int k = 4;<br />
H. Protected int k = 4;<br />
Answer: A, B, C<br />
QUESTION NO: 90<br />
Given:<br />
310-025<br />
Leading the way in IT testing and certification tools, www.testking.com<br />
- 48 -<br />
1. public class foo {<br />
2. static String s;<br />
3. public static void main (String[]args) {<br />
4. system.out.printIn (“s=” + s);<br />
5. }<br />
6. }<br />
What is the result?<br />
A. The code compiles and “s=” is printed.<br />
B. The code compiles and “s=null” is printed.<br />
C. The code does not compile because string s is not initialized.<br />
D. The code does not compile because string s cannot be referenced.<br />
E. The code compiles, but a NullPointerException is thrown when toString is called.<br />
Answer: B<br />
QUESTION NO: 91<br />
Which two valid declarations of a char? (Choose Two)<br />
A. Char ch = “a”;<br />
B. Char ch = ‘\’ ‘;<br />
C. Char ch = ‘cafe’;<br />
D. Char ch = “cafe”;<br />
E. Char ch = ‘\ucafe’;<br />
F. Char ch = ‘\u10100’;<br />
G. Char ch = (char) true;<br />
Answer: B, E<br />
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