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interface A {
void m1(); // 1
public void m2(); // 2
protected void m3(); // 3
private void m4(); // 4
}
Compile-time errors are generated at which lines?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
Which of the following are modifiers that can be applied to a method declaration within an interface?
| a. | abstract |
| b. | final |
| c. | private |
| d. | protected |
| e. | public |
Which of the following is a modifier that can be applied to a method declaration within an interface?
| a. | static |
| b. | synchronized |
| c. | transient |
| d. | volatile |
| e. | native |
| f. | None of the above |
interface A {void m1();} // 1
class B implements A {public void m1() {}} // 2
class C implements A {protected void m1() {}} // 3
class D implements A {private void m1() {}} // 4
class E implements A {void m1() {}} // 5
Compile-time errors are generated at which lines?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | 5 |
Which of the following are true statements?
| a. | The relationship between a class and its superclass is an example of a "has-a" relationship. |
| b. | The relationship between a class and its superclass is an example of an "is-a" relationship. |
| c. | The relationship between a class and an object referenced by a field within the class is an example of a "has-a" relationship. |
| d. | The relationship between a class and an object referenced by a field within the class is an example of an "is-a" relationship. |
interface A {
void m1(); // 1
public void m2(); // 2
protected void m3(); // 3
private void m4(); // 4
abstract void m5(); // 5
}
Compile-time errors are generated at which lines?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | 5 |
interface A {
final void m1(); // 1
synchronized void m2(); // 2
native void m3(); // 3
abstract void m4(); // 4
public void m5(); // 5
}
Compile-time errors are generated at which lines?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | 5 |
interface A {void main(String[] args);} // 1
interface B {public void main(String[] args);} // 2
interface C {public static void main(String[] args);} // 3
interface D {protected void main(String[] args);} // 4
interface E {private void main(String[] args);} // 5
Which interface declarations generate a Compile-time error?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | 5 |
interface F {abstract void main(String[] args);} // 1
interface G {synchronized void main(String[] args);} // 2
interface H {final void main(String[] args);} // 3
interface I {native void main(String[] args);} // 4
Which interface declaration does not generate a compile-time error?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | None of the above |
interface A {String s1 = "A"; String m1();}
interface B implements A {String s1 = "B"; String m1();}
class C implements B {
public String m1() {return s1;}
public static void main(String[] args) {
A a = new C(); System.out.print(a.m1());
}}
What is the result of attempting to compile and run the program?
| a. | Prints: A |
| b. | Prints: B |
| c. | Compile-time error |
| d. | Run-time error |
| e. | None of the above |
interface A {int i = 1; int m1();}
interface B extends A {int i = 10; int m1();}
class C implements B {
public int m1() {return ++i;}
public static void main(String[] args) {
System.out.print(new C().m1());
}}
What is the result of attempting to compile and run the program?
| a. | Prints: 2 |
| b. | Prints: 11 |
| c. | Compile-time error |
| d. | Run-time error |
| e. | None of the above |
interface Z {void m1();} // 1
class A implements Z {void m1() {}} // 2
class B implements Z {public void m1() {}} // 3
abstract class C implements Z {public abstract void m1();} // 4
A Compile-time error is generated at which line?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | None of the above |
interface Z {void m1();} // 1
class D implements Z {public final void m1() {}} // 2
class E implements Z {public synchronized void m1() {}} // 3
class G implements Z {public native void m1();} // 4
A Compile-time error is generated at which line?
| a. | 1 |
| b. | 2 |
| c. | 3 |
| d. | 4 |
| e. | None of the above |
class Leg{}
class Fur{}
abstract class Pet {
public abstract void eat();
public abstract void sleep();
}
class Dog extends Pet {
Leg leftFront = new Leg(), rightFront = new Leg();
Leg leftRear = new Leg(), rightRear = new Leg();
Fur fur = new Fur();
public Fur shed() {return fur;}
public void eat() {}
public void sleep() {}
}
class Cat extends Dog {
public void ignoreOwner() {}
public void climbTree() {}
}
Which of the following statements is not a true statement?
| a. | A Cat object inherits an instance of Fur and four instances of Leg from the Dog superclass. |
| b. | A Cat object is able to sleep and eat. |
| c. | A Cat object is able to climb a tree. |
| d. | The relationship between Dog and Pet is an example of an appropriate use of inheritance. |
| e. | The relationship between Cat and Dog is an example of an appropriate use of inheritance. |
| f. | None of the above. |
class A {
A() {System.out.print("CA ");}
static {System.out.print("SA ");}
}
class B extends A {
B() {System.out.print("CB ");}
static {System.out.print("SB ");}
public static void main (String[] args) {B b = new B();}
}
What is the result of attempting to compile and run the above program?
| a. | Prints: SA CA SB CB |
| b. | Prints: SA SB CA CB |
| c. | Prints: SB SA CA CB |
| d. | Prints: SB CB SA CA |
| e. | Runtime Exception |
| f. | Compiler Error |
| g. | None of the above |
interface I10 {String name = "I10"; String s10 = "I10.s10";}
interface I20 {String name = "I20"; String s20 = "I20.s20";}
class C10 implements I10, I20 { // 1
public static void main(String[] args) {
System.out.print(s10+","); // 2
System.out.print(s20+","); // 3
System.out.print(name); // 4
}}
What is the result of attempting to compile and run the program?
| a. | Prints: I10.s10,I20.s20,I10 |
| b. | Prints: I10.s10,I20.s20,I20 |
| c. | Prints: I10.s10,I20.s20, |
| d. | Prints: I10.s10,I20.s20,null |
| e. | Compile-time error at line 1 |
| f. | Compile-time error at line 2 |
| g. | Compile-time error at line 3 |
| h. | Compile-time error at line 4 |
| i. | Run-time error |
| j. | None of the above |
interface I10 {String name = "I10"; String s10 = "I10.s10";}
interface I20 {String name = "I20"; String s20 = "I20.s20";}
class C20 implements I10, I20 { // 1
public static void main(String[] args) {
System.out.print(I10.s10+","); // 2
System.out.print(I20.s20+","); // 3
System.out.print(I20.name); // 4
}}
What is the result of attempting to compile and run the program?
| a. | Prints: I10.s10,I20.s20,I10 |
| b. | Prints: I10.s10,I20.s20,I20 |
| c. | Prints: I10.s10,I20.s20, |
| d. | Prints: I10.s10,I20.s20,null |
| e. | Compile-time error at line 1 |
| f. | Compile-time error at line 2 |
| g. | Compile-time error at line 3 |
| h. | Compile-time error at line 4 |
| i. | Run-time error |
| j. | None of the above |
class A {String s1="A";}
class B extends A {String s1="B";}
class C extends B {String s1="C";}
class D extends C {
String s1="D";
void m1() {
System.out.print(this.s1 + ","); // 1
System.out.print(((C)this).s1 + ","); // 2
System.out.print(((B)this).s1 + ","); // 3
System.out.print(((A)this).s1); // 4
}
public static void main (String[] args) {
new D().m1(); // 5
}}
What is the result of attempting to compile and run the program?
| a. | Prints: D,D,D,D |
| b. | Prints: D,C,B,A |
| c. | Compile-time error at 1. |
| d. | Compile-time error at 2. |
| e. | Compile-time error at 3. |
| f. | Compile-time error at 4. |
| g. | Compile-time error at 5. |
| h. | Run-time error |
| i. | None of the above |
class SuperA {String s1="SuperA";}
class SuperB {String s1="SuperB";}
class A extends SuperA {
String s1="A";
class B extends SuperB { // 1
String s1="B";
void m1() {
System.out.print(this.s1 + ","); // 2
System.out.print(super.s1 + ","); // 3
System.out.print(A.this.s1 + ","); // 4
System.out.print(A.super.s1); // 5
}
}
public static void main (String[] args) {
new A().new B().m1(); // 6
}}
What is the result of attempting to compile and run the program?
| a. | Prints: B,SuperB,B,SuperB |
| b. | Prints: B,SuperB,A,SuperA |
| c. | Compile-time error at 1. |
| d. | Compile-time error at 2. |
| e. | Compile-time error at 3. |
| f. | Compile-time error at 4. |
| g. | Compile-time error at 5. |
| h. | Compile-time error at 6. |
| i. | Run-time error |
| j. | None of the above |
class A {void m1() {System.out.print("A");}}
class B extends A {void m1(){System.out.print("B");}}
class C extends B {void m1() {System.out.print("C");}}
class D extends C {
void m1() {System.out.print("D");}
void m2() {
m1();
((C)this).m1(); // 1
((B)this).m1(); // 2
((A)this).m1(); // 3
}
public static void main (String[] args) {
new D().m2(); // 4
}}
What is the result of attempting to compile and run the program?
| a. | Prints: DCBA |
| b. | Prints: DDDD |
| c. | Compile-time error at 1. |
| d. | Compile-time error at 2. |
| e. | Compile-time error at 3. |
| f. | Compile-time error at 4. |
| g. | Run-time error |
| h. | None of the above |
class A {public void m1() {System.out.print("A1");}}
class B extends A {
public void m1() {System.out.print("B1");}
public void m2() {System.out.print("B2");}
}
class C {
public static void main(String[] args) {
A a1 = new B();
a1.m1(); // 1
a1.m2(); // 2
((B)a1).m1(); // 3
((B)a1).m2(); // 4
}}
What is the result of attempting to compile and run the program?
| a. | Prints: A1B2B1B2 |
| b. | Prints: B1B2B1B2 |
| c. | Compile-time error at 1 |
| d. | Compile-time error at 2 |
| e. | Compile-time error at 3 |
| f. | Compile-time error at 4 |
| g. | Run-time error |
| h. | None of the above |