JAVA Interfaces and Abstract Classes In Java, declaring a class abstract is useful When it doesn't make sense to have objects of that class. When it makes sense to have objects of that class. When default implementations of some methods are not desirable. To prevent developers from further extending the class. To force developers to extend the class not to use its capabilities. When it doesn't make sense to have objects of that class. When it makes sense to have objects of that class. When default implementations of some methods are not desirable. To prevent developers from further extending the class. To force developers to extend the class not to use its capabilities. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a default constructor. Which of the following is correct?1. A a = new A();2. A a = new B();3. B b = new A();4. B b = new B(); 1 and 2 3 and 4 2 and 3 2 and 4 1 and 3 1 and 2 3 and 4 2 and 3 2 and 4 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Given the following piece of code:public class School{ public abstract double numberOfStudent();}which of the following statements is true? The method numberOfStudent() in class School must have a body. You must add a return statement in method numberOfStudent(). The keywords public and abstract cannot be used together. Class School must be defined abstract. The method numberOfStudent() in class School must have a body. You must add a return statement in method numberOfStudent(). The keywords public and abstract cannot be used together. Class School must be defined abstract. ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which of the following declares an abstract method in an abstract Java class? public abstract void method() {} public abstract method(); public void method() {} public abstract void method(); public void abstract Method(); public abstract void method() {} public abstract method(); public void method() {} public abstract void method(); public void abstract Method(); ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes Which two of the following are legal declarations for abstract classes and interfaces?1. final abstract class Test {}2. public static interface Test {}3. final public class Test {}4. protected abstract class Test {}5. protected interface Test {}6. abstract public class Test {} 5 and 6 2 and 4 3 and 5 3 and 6 1 and 2 5 and 6 2 and 4 3 and 5 3 and 6 1 and 2 ANSWER DOWNLOAD EXAMIANS APP
JAVA Interfaces and Abstract Classes interface Base{ boolean m1 (); byte m2(short s);}which two code fragments will compile?1. interface Base2 implements Base {}2. abstract class Class2 extends Base { public boolean m1(){ return true; }}3. abstract class Class2 implements Base {}4. abstract class Class2 implements Base { public boolean m1(){ return (7 > 4); }}5. abstract class Class2 implements Base { protected boolean m1(){ return (5 > 7) }} 4 and 5 1 and 3 3 and 4 2 and 3 1 and 2 4 and 5 1 and 3 3 and 4 2 and 3 1 and 2 ANSWER DOWNLOAD EXAMIANS APP
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