Question

1. We want to create and then initialize an array named A to contain the integers: 4, 5, 6, 7.

There are multiple ways this can be done. From the list below, select all of the correct ways to create and initialize A.

1. int size = 4;

int [] A = new int [size];

A[0] = 4;

A[1] = 5;

A[2] = 6;

A[3] = 7;

2. int [] A = new int [4];

      A[0] = 4;

      A[1] = 5;

      A[2] = 6;

     A[3] = 7;

3. int [] = {4, 5, 6, 7};
4. int size = 4;

int [] A = new int [size];

A = {4, 5, 6, 7};

5. int A = new int[4];

A = {4, 5, 6, 7};

2. Choose the correct ans to initialize an Integer object named num with the value 225.

1. num = new Integer(255);
2. int num = 255;
3. Int num = 255;
4. Integer num = new Integer(255);

3. Given this ArrayList declaration of lastNames:

             ArrayList <String> lastNames = new ArrayList<>();

lastNames.add("Peter");

lastNames.add("Karter");

lastNames.add("Larry");

What operation(s) would we perform to replace "Peter" with "Meter"?

1. lastNames.set(0, "Meter");
2. lastNames[0] = "Meter";
3. lastNames.remove(0); lastNames.add("Meter");

Answer 1

Answers are

Q1)

Correct Method to create and initialize A are Options A,B

Others option are not correct

Q2)

Answer is Option D

Integer num = new Integer(255) is to initialize an Integer Object

Q3)

Answer is Option A

To replace existing element of Array List in Java. We use Set () method And Set method take two arguments first is the index and second is the new value that you want to insert

So lastNames.set(0, "Meter"); is Correct

These are the Solution for the given problems

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