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SCJP模拟试题[1](2)
添加时间: 2007-9-23 1:55:23 作者: JAVA题库 阅读次数:54 来源: http://www.d9soft.com
add(b);
}
class ClickHandler extends MouseAdapter {
public void mouseClicked(MouseEvent evt) {
// A
}
}
}
What line of code at A writes the mouse’s horizontal location to the standard output at the time of the event?
Fill in the blank.
----------------------------
Question 12: Given the same code as in question 10, how can you write a line of code at A that will place the Button object into a variable named mybutton that is already defined to be a reference to a Button object?
Fill in the blank.
-----------------------------------------
Question 13: Which Listener interface can you implement to be able to respond to the user hitting the enter key after typing into a TextField object?
Fill in the blank.
---------------------------------------
Question 14: What is written to the standard output as the result of executing the following statements?
Boolean b1 = new Boolean(true);
Boolean b2 = new Boolean(true);
if (b1 == b2)
if (b1.equals(b2))
System.out.println("a");
else
System.out.println("b");
else
if (b1.equals(b2))
System.out.println("c");
else
System.out.println("d");
Select the one right answer.
a) a
b) b
c) c
d) d
---------------------------------------
Question 15: Which Listener interfaces can you add to a TextArea object?
a) TextListener
b) ActionListener
c) MouseMotionListener
d) MouseListener
e) ComponentListener
-------------------------------------
Question 16: What appears in the standard output if the method named problem() in the code below throws an instance of class Exception when the method named trythis() is invoked?
public void trythis() {
try {
System.out.println("1");
problem();
} catch (RuntimeException x) {
System.out.println("2");
return;
} catch (Exception x) {
System.out.println("3");
return;
} finally {
System.out.println("4");
}
System.out.println("5");
}
Select all valid answers.
a) "1"
b) "2"
c) "3"
d) "4"
e) "5"
------------------------------------------
Question 17: What is the type of the Event object passed to the mouseDragged() method defined in a class that implements java.awt.event.MouseMotionListener (that is, what is the class name for the argument)?
Fill in the blank.
----------------------------------------
Question 18: Examine the following switch block:
char mychar = 'c';
switch (mychar) {
default:
case 'a': System.out.println("a"); break;
case 'b': System.out.println("b"); break;
}
Which of the following questions are definitely true?
Select all valid answers.
a) This switch block is illegal, because only integers can be used in the switch statement.
b) This switch block is fine.
c) This switch block is illegal, because the default statement must come last.
d) When this code runs, nothing is written to the standard output.
e) When this code runs, the letter "a" is written to the standard output.
---------------------------
Question 19: What keyword must appear in a method declaration (followed by the name of the exception) when that method might cause an exception to be thrown and that method does not handle the exception?
Fill in the blank.
--------------------------------
Question 20: Which statements accurately describe the following line of code?
Select all valid answers.
String[][] s = new String[10][];
a) This line of code is illegal.
b) s is a two-dimensional array containing 10 rows and 10 columns
c) s is an array of 10 arrays.
d) Each element in s is set to ""
e) Each element in s is uninitialized and must be initialized before it is referenced.
Question 21: What will happen if you try to compile and run the following class?
class Test {
static int myArg = 1;
public static void main(String[] args) {
int myArg;
System.out.println(myArg);
}
}
Select the one right answer.
a) This code compiles and displays 0 in the standard output when run.
b) This code compiles and displays 1 in the standard output when run.
c) This code does not compile because you cannot define a local variable named the same as a static variable.
d) This code does not compile because the local variable is used before it is initialized.
--------------------------------------
Question 22: Which declarations for the main() method in a stand-alone program are NOT valid?
Select all valid answers.
a) public static void main()
b) public static void main(String[] string)
c) public static void main(String args)
d) static public int main(String[] args)
e) static void main(String[] args)
---------------------------------------
Question 23: Which of the following identifiers are ILLEGAL?
Select all valid answers.
a) #_pound
b) _underscore
c) 5Interstate
d) Interstate5
e) _5_
--------------------------------------
Question 24: If the user invokes a stand-alone application by typing:
java YourApp 1 2 3
and the main() method defines its String[] parameter as args, how can you access the number 2 using args?
Fill in the blank.
--------------------------------
Question 25: Which interface implementations can you add as listeners for a TextField object?
Select all valid answers.
a) ActionListener
b) FocusListener
c) MouseMotionListener
d) WindowListener
e) ContainerListener
------------------------------------------
Question 26: What must be true for the RunHandler class so that instances of RunHandler can be used as written in the code below:
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