In which two cases does the compiler supply a default constructor for class A?() A、 class A{}B、 class A { public A(){} }C、 class A { public A(int x){} }D、 class Z {} class A extends Z { void A(){} }
In which two cases does the compiler supply a default constructor for class A?()
- A、 class A{}
- B、 class A { public A(){} }
- C、 class A { public A(int x){} }
- D、 class Z {} class A extends Z { void A(){} }
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Given:Which two, inserted at line 11, will allow the code to compile?() A.public class MinMax? {B.public class MinMax? extends Number {C.public class MinMaxN extends Object {D.public class MinMaxN extends Number {E.public class MinMax? extends Object {F.public class MinMaxN extends Integer {
public class SomeException { } Class a: public class a { public void doSomething() { } } Class b: public class b extends a { public void doSomething() throws SomeException { } } Which is true about the two classes?() A、 Compilation of both classes will fail.B、 Compilation of both classes will succeed.C、 Compilation of class a will fail. Compilation of class b will succeed.D、 Compilation of class a will fail. Compilation of class a will succeed.
class A { A() { } } class B extends A { } Which two statements are true?()A、 Class B’s constructor is public.B、 Class B’s constructor has no arguments.C、 Class B’s constructor includes a call to this().D、 Class B’s constructor includes a call to super().
Which two statements are true regarding the creation of a default constructor?() A、 The default constructor initializes method variables.B、 The compiler always creates a default constructor for every class.C、 The default constructor invokes the no-parameter constructor of the superclass.D、 The default constructor initializes the instance variables declared in the class.E、 When a class has only constructors with parameters, the compiler does not create a default constructor.
Which statements concerning the following code are true?() class a { public a() {} public a(int i) { this(); } } class b extends a { public boolean b(String msg) { return false; } } class c extends b { private c() { super(); } public c(String msg) { this(); } public c(int i) {} } A、The code will fail to compile.B、The constructor in a that takes an int as an argument will never be called as a result of constructing an object of class b or c.C、Class c has three constructors.D、Objects of class b cannot be constructed.E、At most one of the constructors of each class is called as a result of constructing an object of class c.
interface Data { public void load(); } abstract class Info { public abstract void load(); } Which class correctly uses the Data interface and Info class?() A、 public class Employee extends Info implements Data { public void load() { /*do something*/ } }B、 public class Employee implements Info extends Data { public void load() { /*do something*/ } }C、 public class Employee extends Info implements Data { public void load() { /*do something */ } public void Info.load() { /*do something*/ } }D、 public class Employee implements Info extends Data { public void Data.load() { /*dsomething */ } public void load() { /*do something */ } }E、 public class Employee implements Info extends Data { public void load() { /*do something */ } public void Info.load(){ /*do something*/ } }F、 public class Employee extends Info implements Data{ public void Data.load() { /*do something*/ } public void Info.load() { /*do something*/ } }
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Which statements, when inserted at the indicated position in the following code, will cause a runtime exception when attempting to run the program?() class A {} class B extends A {} class C extends A {} public class Q3ae4 { public static void main(String args[]) { A x = new A(); B y = new B(); C z = new C(); // insert statement here } } A、x = y;B、z = x;C、y = (B) x;D、z = (C) y;E、y = (A) y;
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多选题public abstract class Shape { private int x; private int y; public abstract void draw(); public void setAnchor(int x, int y) { this.x = x; this.y = y; } } Which two classes use the Shape class correctly?()Apublic class Circle implements Shape { private int radius; }Bpublic abstract class Circle extends Shape { private int radius; }Cpublic class Circle extends Shape { private int radius; public void draw(); }Dpublic abstract class Circle implements Shape { private int radius; public void draw(); }Epublic class Circle extends Shape { private int radius;public void draw() {/* code here */} }Fpublic abstract class Circle implements Shape { private int radius;public void draw() { / code here */ } }
单选题interface Data { public void load(); } abstract class Info { public abstract void load(); } Which class correctly uses the Data interface and Info class?()A public class Employee extends Info implements Data { public void load() { /*do something*/ } }B public class Employee implements Info extends Data { public void load() { /*do something*/ } }C public class Employee extends Info implements Data { public void load() { /*do something */ } public void Info.load() { /*do something*/ } }D public class Employee implements Info extends Data { public void Data.load() { /*dsomething */ } public void load() { /*do something */ } }E public class Employee implements Info extends Data { public void load() { /*do something */ } public void Info.load(){ /*do something*/ } }F public class Employee extends Info implements Data{ public void Data.load() { /*do something*/ } public void Info.load() { /*do something*/ } }
多选题Which two statements are true regarding the creation of a default constructor?()AThe default constructor initializes method variables.BThe compiler always creates a default constructor for every class.CThe default constructor invokes the no-parameter constructor of the superclass.DThe default constructor initializes the instance variables declared in the class.EWhen a class has only constructors with parameters, the compiler does not create a default constructor.
单选题What produces a compiler error?()A class A { public A(int x) {} }B class A {} class B extends A { B() {} }C class A { A() {} } class B { public B() {} }D class Z { public Z(int) {} } class A extends Z {}
多选题Which two allow the class Thing to be instantiated using new Thing()?Apublic class Thing { }Bpublic class Thing { public Thing() {} }Cpublic class Thing { public Thing(void) {} }Dpublic class Thing { public Thing(String s) {} }Epublic class Thing { public void Thing() {} public Thing(String s) {} }