11. class Person {
12. String name = “No name‟;
13. public Person(String nm) { name = nm; }
14. }
15.
16. class Employee extends Person {
17. String emplD = “0000”;
18. public Employee(String id) { empID = id; }
19. }
20.
21. public class EmployeeTest {
22. public static void main(String[] args) {
23. Employee e = new Employee(”4321”);
24. System.out.println(e.empID);
25. }
26. }
What is the result?()
A. 4321
B. 0000
C. An exception is thrown at runtime.
D. Compilation fails because of an error in line 18.
您可能感兴趣的试卷
你可能感兴趣的试题
class One {
public One() { System.out.print(1); }
}
class Two extends One {
public Two() { System.out.print(2); }
}
class Three extends Two {
public Three() { System.out.print(3); }
}
public class Numbers{
public static void main( String[] argv) { new Three(); }
}
What is the result when this code is executed?()
A. 1
B. 3
C. 123
D. 321
E. The code rims with no output.
10. class Line {
11. public class Point { public int x,y; }
12. public Point getPoint() { return new Point(); }
13. }
14. class Triangle {
15. public Triangle() {
16. // insert code here
17. }
18. }
Which code, inserted at line 16, correctly retrieves a local instance of a Point object?()
A. Point p = Line.getPoint();
B. Line.Point p = Line.getPoint();
C. Point p = (new Line()).getPoint();
D. Line.Point p = (new Line()).getPoint();
10. class Line {
11. public static class Point { }
12. }
13.
14. class Triangle {
15. // insert code here
16. }
Which code, inserted at line 15, creates an instance of the Point class defined in Line?()
A. Point p = new Point();
B. Line.Point p = new Line.Point();
C. The Point class cannot be instatiated at line 15.
D. Line 1 = new Line() ; 1.Point p = new 1.Point();
1. public class A {
2. public void doit() {
3. }
4. public String doit() {
5. return “a”;
6. }
7. public double doit(int x) {
8. return 1.0;
9. }
10.}
What is the result?()
A. An exception is thrown at runtime.
B. Compilation fails because of an error in line 7.
C. Compilation fails because of an error in line 4.
D. Compilation succeeds and no runtime errors with class A occur.
1. public class A {
2. public String doit(int x, int y) {
3. return “a”;
4. }
5.
6. public String doit(int... vals) {
7. return “b”;
8. }
9. }
Given:
25. A a=new A();
26. System.out.println(a.doit(4, 5));
What is the result?()
A. Line 26 prints “a” to System.out.
B. Line 26 prints „b” to System.out.
C. An exception is thrown at line 26 at runtime.
D. Compilation of class A will fail due to an error in line 6.
1. public interface A {
2. public void doSomething(String thing);
3. }
1. public class AImpl implements A {
2. public void doSomething(String msg) { }
3. }
1. public class B {
2. public A doit() {
3. // more code here
4. }
5.
6. public String execute() {
7. // more code here
8. }
9. }
1. public class C extends B {
2. public AImpl doit() {
3. // more code here
4. }
5.
6. public Object execute() {
7. // more code here
8. }
9. }
Which statement is true about the classes and interfaces in the exhibit?()
A. Compilation will succeed for all classes and interfaces.
B. Compilation of class C will fail because of an error in line 2.
C. Compilation of class C will fail because of an error in line 6.
D. Compilation of class AImpl will fail because of an error in line 2.
class One {
void foo() {}
}
class Two extends One {
//insert method here
}
Which three methods, inserted individually at line 14, will correctly complete class Two?()
A. int foo() { /* more code here */ }
B. void foo() { /* more code here */ }
C. public void foo() { /* more code here */ }
D. private void foo() { /* more code here */ }
E. protected void foo() { /* more code here */ }
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; }
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.
最新试题
Which statement is true about the set variable on line 12?()
What is the result?()
Which statement is true?()
Which three changes should be made to adapt this class to be used safely by multiple threads?()
What is the result?()
Which two changes, taken together, would guarantee the output: 1, 2, 3, 4, 5?()
A programmer iterates over the TreeSet and prints the name of each Drink object. What is the result?()
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()?()
What is the result?()
Given that t1 is a reference to a live thread, which is true?()