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1. How many items can be selected from a ComboBox at a time? 0 1 2 Unlimited You

ID: 3570883 • Letter: 1

Question

1.      How many items can be selected from a ComboBox at a time?

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You cannot use Number as a data type since it is an abstract class.

Since each element of numberArray is of the Number type, you cannot assign an Integer object to it.

Since each element of numberArray is of the Number type, you cannot assign a Double object to it.

At runtime, new Integer[2] is assigned to numberArray. This makes each element of numberArray an Integer object. So you cannot assign a Double object to it.

Which of the following statements are true about abstract classes?

An abstract method cannot be contained in a nonabstract class.

If a subclass of an abstract superclass does not implement all the abstract methods, the subclass must be declared abstract.

An abstract class cannot be instantiated using the new operator.

It is possible to declare an abstract class that contains no abstract methods.

A subclass can be abstract even if its superclass is concrete.

Why is JavaFX preferred?

JavaFX is much simpler to learn and use for new Java programmers.

JavaFX provides a multi-touch support for touch-enabled devices such as tablets and smart phones.

JavaFX has a built-in 3D, animation support, video and audio playback, and runs as a standalone application or from a browser.

JavaFX incorporates modern GUI technologies to enable you to develop rich Internet applications.

)   In the following code which is the error? (Assume all ellipses ... represent valid Java instructions.)

public class Parent {

                private String name=Object;

                private String type=;

               public Parent(){

.

               }

}

public class Child extends Parent {

               public Child(){

.

               }

               public Child(double newName){

                    this.name=newName;

.

               }

}

Nothing is wrong.

A class which extends (inherits from) another class must NOT have its own constructor.

The private variable inherited from the parent cannot be changed.

Mismatch of variable type.

Suppose ArrayList<Double>list = new ArrayList<Double>(). Which of the following statements are correct?

list.add(5.5); // 5.5 is automatically converted to new Double(5.5)

list.add(3.0); // 3.0 is automatically converted to new Double(3.0)

Double doubleObject = list.get(0); // No casting is needed

double d = list.get(1); // Automatically converted to double

The statement for registering a listener for processing slider change is ________.

sl.addListener(e -> {processStatements});

sl.getValue().addListener(e -> {processStatements});

sl.valueProperty().addListener(e -> {processStatements});

sl.getItems().addListener(e -> {processStatements});

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1. How many items can be selected from a ComboBox at a time? 1. Analyze the following code. Which of the following statements are true about abstract classes? Why is JavaFX preferred? In the following code which is the error? (Assume all ellipses ... represent valid Java instructions.) Suppose ArrayList list = new ArrayList (). Which of the following statements are correct? The statement for registering a listener for processing slider change is ________.

Explanation / Answer

Answer:

1.How many items can be selected from a ComboBox at a time?

Anwer: 1

2. Answr: At runtime, new Integer[2] is assigned to numberArray. This makes each element of numberArray an Integer object. So you cannot assign a Double object to it.

3.Answer: If a subclass of an abstract superclass does not implement all the abstract methods, the subclass must be declared abstract.

4.Why is JavaFX preferred?

Answer: JavaFX incorporates modern GUI technologies to enable you to develop rich Internet applications.

5.Answer : Nothing is wrong.

6.Answer: double d = list.get(1); // Automatically converted to double

7.The statement for registering a listener for processing slider change is ?

Answer: sl.addListener(e -> {processStatements});