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Declarations And Access Control Online Exam Quiz

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1. Which two cause a compiler error? float[ ] f = new float(3); float f2[ ] = new float[ ]; float[ ]f1 = new float[3]; float f3[ ] = new float[3]; float f5[ ] = {1.0f, 2.0f, 2.0f};

Options

A : 2, 4

B : 3, 5

C : 4, 5

D : 1, 2

2. You want a class to have access to members of another class in the same package. Which is the most restrictive access that accomplishes this objective?

Options

A : public

B : private

C : protected

D : default access

3. What is the prototype of the default constructor? public class Test { }

Options

A : Test( )

B : Test(void)

C : public Test( )

D : public Test(void)

4. Which cause a compiler error?

Options

A : int[ ] scores = {3, 5, 7};

B : int [ ][ ] scores = {2,7,6}, {9,3,45};

C : String cats[ ] = {"Fluffy", "Spot", "Zeus"};

D : boolean results[ ] = new boolean [] {true, false, true};

5. Which two code fragments will compile? interface Base2 implements Base {} abstract class Class2 extends Base { public boolean m1(){ return true; }} abstract class Class2 implements Base {} abstract class Class2 implements Base { public boolean m1(){ return (7 > 4); }} abstract class Class2 implements Base { protected boolean m1(){ return (5 > 7) }} interface Base { boolean m1 (); byte m2(short s); }

Options

A : 1 and 2

B : 2 and 3

C : 3 and 4

D : 1 and 5

6. You want subclasses in any package to have access to members of a superclass. Which is the most restrictive access that accomplishes this objective?

Options

A : public

B : private

C : protected

D : transient

7. Which one creates an instance of an array?

Options

A : int[ ] ia = new int[15];

B : float fa = new float[20];

C : char[ ] ca = "Some String";

D : int ia[ ] [ ] = { 4, 5, 6 }, { 1,2,3 };

8. What is the widest valid returnType for methodA in line 3? public class ReturnIt { returnType methodA(byte x, double y) /* Line 3 */ { return (long)x / y * 2; } }

Options

A : int

B : byte

C : long

D : double

9. What will be the output of the program? interface Count { short counter = 0; void countUp(); } public class TestCount implements Count { public static void main(String [] args) { TestCount t = new TestCount(); t.countUp(); } public void countUp() { for (int x = 6; x>counter; x--, ++counter) /* Line 14 */ { System.out.print(" " + counter); } } }

Options

A : 0 1 2

B : 1 2 3

C : 0 1 2 3

D : 1 2 3 4

10. What will be the output of the program? public class A { void A() /* Line 3 */ { System.out.println("Class A"); } public static void main(String[] args) { new A(); } }

Options

A : Class A

B : Compilation fails.

C : An exception is thrown at line 3.

D : The code executes with no output.

1. What will be the output of the program? import java.util.*; public class NewTreeSet2 extends NewTreeSet { public static void main(String [] args) { NewTreeSet2 t = new NewTreeSet2(); t.count(); } } protected class NewTreeSet { void count() { for (int x = 0; x < 7; x++,x++ ) { System.out.print(" " + x); } } }

Options

A : 0 2 4

B : 0 2 4 6

C : Compilation fails at line 2

D : Compilation fails at line 10

2. What will be the output of the program? public class Test { public static void main(String args[]) { class Foo { public int i = 3; } Object o = (Object)new Foo(); Foo foo = (Foo)o; System.out.println("i = " + foo.i); } }

Options

A : i = 3

B : Compilation fails.

C : i = 5

D : A ClassCastException will occur.

3. What will be the output of the program? public class ArrayTest { public static void main(String[ ] args) { float f1[ ], f2[ ]; f1 = new float[10]; f2 = f1; System.out.println("f2[0] = " + f2[0]); } }

Options

A : It prints f2[0] = 0.0

B : It prints f2[0] = NaN

C : An error at f2 = f1; causes compile to fail.

D : It prints the garbage value.

4. What will be the output of the program? public class Test { public int aMethod() { static int i = 0; i++; return i; } public static void main(String args[]) { Test test = new Test(); test.aMethod(); int j = test.aMethod(); System.out.println(j); } }

Options

A : 0

B : 1

C : 2

D : Compilation fails.

5. What will be the output of the program? class Super { public Integer getLength() { return new Integer(4); } } public class Sub extends Super { public Long getLength() { return new Long(5); } public static void main(String[] args) { Super sooper = new Super(); Sub sub = new Sub(); System.out.println( sooper.getLength().toString() + "," + sub.getLength().toString() ); } }

Options

A : 4, 4

B : 4, 5

C : 5, 4

D : Compilation fails.

6. What will be the output of the program? class Super { public int i = 0; public Super(String text) /* Line 4 */ { i = 1; } } class Sub extends Super { public Sub(String text) { i = 2; } public static void main(String args[]) { Sub sub = new Sub("Hello"); System.out.println(sub.i); } }

Options

A : 0

B : 1

C : 2

D : Compilation fails.

7. What will be the output of the program? class Base { Base() { System.out.print("Base"); } } public class Alpha extends Base { public static void main(String[] args) { new Alpha(); /* Line 12 */ new Base(); /* Line 13 */ } }

Options

A : Base

B : BaseBase

C : Compilation fails

D : The code runs with no output

8. What will be the output of the program? class A { final public int GetResult(int a, int b) { return 0; } } class B extends A { public int GetResult(int a, int b) {return 1; } } public class Test { public static void main(String args[]) { B b = new B(); System.out.println("x = " + b.GetResult(0, 1)); } }

Options

A : x = 0

B : x = 1

C : Compilation fails.

D : An exception is thrown at runtime.

1. Which of the following class level (nonlocal) variable declarations will not compile?

Options

A : protected int a;

B : transient int b = 3;

C : private synchronized int e;

D : volatile int d;

2. Given a method in a protected class, what access modifier do you use to restrict access to that method to only the other members of the same class?

Options

A : final

B : static

C : private

D : protected

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