class One {
public One foo() { return this; }
}
class Two extends One {
public One foo() { return this; }
}
class Three extends Two {
// insert method here
}
Which two methods, inserted individually, correctly complete the Three class?()
A. public void foo() { }
B. public int foo() { return 3; }
C. public Two foo() { return this; }
D. public One foo() { return this; }
E. public Object foo() { return this; }
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A JavaBeans component has the following field:
11. private boolean enabled;
Which two pairs of method declarations follow the JavaBeans standard for accessing this field?()
A. public void setEnabled( boolean enabled) public boolean getEnabled()
B. public void setEnabled( boolean enabled) public void isEnabled()
C. public void setEnabled( boolean enabled) public boolean isEnabled()
D. public boolean setEnabled( boolean enabled) public boolean getEnabled()
1. public class A {
2.
3. private int counter = 0;
4.
5. public static int getInstanceCount() {
6. return counter;
7. }
8.
9. public A() {
10. counter++;
11. }
12.
13. }
Given this code from Class B:
25.A a1 =new A();
26. A a2 =new A();
27. A a3 =new A();
28. System.out.printIn(A.getInstanceCount() );
What is the result?()
A. Compilation of class A fails.
B. Line 28 prints the value 3 to System.out.
C. Line 28 prints the value 1 to System.out.
D. A runtime error occurs when line 25 executes.
E. Compilation fails because of an error on line 28.
A programmer is designing a class to encapsulate the information about an inventory item. A JavaBeans component is needed to do this. The Inventoryltem class has private instance variables to store the item information:
10. private int itemId;
11. private String name;
12. private String description;
Which method signature follows the JavaBeans naming standards for modifying the itemld instance variable?()
A. itemID(int itemId)
B. update(int itemId)
C. setItemId(int itemId)
D. mutateItemId(int itemId)
E. updateItemID(int itemId)
A programmer needs to create a logging method that can accept an arbitrary number of arguments. For example, it may be called in these ways:
logIt(”log message 1 “);
logIt(”log message2”,”log message3”);
logIt(”log message4”, “log message5”, “log message6);
Which declaration satisfies this requirement?()
A. public void logIt(String * msgs)
B. public void logIt(String [] msgs)
C. public void logIt(String... msgs)
D. public void logIt(String msg1, String msg2, String msg3)
10. class Foo {
11. static void alpha() { /* more code here */ }
12. void beta() { /* more code here */ }
13. }
Which two are true?()
A. Foo.beta() is a valid invocation of beta().
B. Foo.alpha() is a valid invocation of alpha().
C. Method beta() can directly call method alpha().
D. Method alpha() can directly call method beta().
11. public static void main(String[] args) {
12. Object obj =new int[] { 1,2,3 };
13. int[] someArray = (int[])obj;
14. for (int i: someArray) System.out.print(i +“ “)
15. }
What is the result? ()
A. 1 2 3
B. Compilation fails because of an error in line 12.
C. Compilation fails because of an error in line 13.
D. Compilation fails because of an error in line 14.
E. A ClassCastException is thrown at runtime.
11. public enum Title {
12. MR(”Mr.”), MRS(”Mrs.”), MS(”Ms.”);
13. private final String title;
14. private Title(String t) { title = t; }
15. public String format(String last, String first) {
16. return title + “ “ + first + “ “ + last;
17. }
18. }
19. public static void main(String[] args) {
20. System.out.println(Title.MR.format(”Doe”, “John”));
21. }
What is the result?()
A. Mr. John Doe
B. An exception is thrown at runtime.
C. Compilation fails because of an error in line 12.
D. Compilation fails because of an error in line 15.
E. Compilation fails because of an error in line 20.
public class Ball {
public enum Color { RED, GREEN, BLUE };
public void foo() {
// insert code here
{ System.out.println(c); }
}
}
Which code inserted at line 14 causes the foo method to print RED, GREEN, and BLUE?()
A. for( Color c : Color.values())
B. for( Color c = RED; c <= BLUE; c++)
C. for( Color c; c.hasNext() ; c.next())
D. for( Color c = Color[0]; c <= Color[2]; c++)
E. for( Color c = Color.RED; c <= Color.BLUE; c++)
A. static final int[] a = { 100,200 };
B. static final int[] a; static { a=new int[2]; a[0]=100; a[1]=200; }
C. static final int[] a = new int[2] { 100,200 };
D. static final int[] a; static void init() { a = new int[3]; a[0]=100; a[1]=200; }
35. String #name = “Jane Doe”;
36. int$age=24;
37. Double_height = 123.5;
38. double~temp = 37.5;
Which two are true?()
A. Line 35 will not compile.
B. Line 36 will not compile.
C. Line 37 will not compile.
D. Line 38 will not compile.
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最新试题
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A programmer must create a generic class MinMax and the type parameter of MinMax must implement Comparable. Which implementation of MinMax will compile?()
Given a class whose instances, when found in a collection of objects, are sorted by using the compareTo() method, which two statements are true?()
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