Concept explainers
Create an ArrayList
If you write the last line without a trailing semicolon, you will see the small red object icon. Drag this icon onto the object bench. Examine its methods and try calling some (such as add, remove, size, isEmpty). Also try calling the same methods from the Code Pad. You can access objects on the object bench from the Code Pad by using their names. For example, if you have an ArrayList named all on the object bench, in the Code Pad you can type:
a11.size()
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- Use the Iterator Pattern: Create a class called Exercise, and then, in its main method, create an ArrayList called stringArrayList. Add the following five strings to stringArrayList: “one”, “two”, ”three”, ”four”, ”five”. Then, use a for loop and the index of stringArrayList to print all these five strings out to the console. 2. For stringArrayList above, can you use an iterator to traverse the five strings inside, without using the index? 3. If change stringArrayList into a TreeSet, how do you traverse the five strings use an iterator? Implement an Iterator: 4. Create a class called StringArray that is able to store a number of String objects. Create an instance variable, String[] values, (internal data storage) of StringArray to store all the strings. 5. Create a constructor for StringArray, which is able to build an object of StringArray using the parameter. public StringArray(String[] values) 6. Make the class StringArray implements Iterable So that it…arrow_forwardFirst, launch NetBeans and close any previous projects that may be open (at the top menu go to File ==> Close All Projects).Then create a new Java application called "Parser" (without the quotation marks) that uses methods to:Get a comma-delimited String of integers (e.g. "4, 8, 16, 32") from the user at the command line and then convert the String to an ArrayList of integers (using the wrapper class) with each element containing one of the input integers in sequencePrint the integers to the command line, using a for loop, so that each integer is on a separate linearrow_forward) Modify the BookStore and BookSearchEngine classes explained in the class to include the following additional methods and test them:a) A method returning the book with the lowest price in the library.b) A method searching the library for Books of a given author and returning an ArrayList of such Books. c) A method returning an ArrayList of Books whose price is less than a given number.arrow_forward
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- In this exercise, you are going to build on your Circleclass from the previous exercise. You are going to add 2 method, areaDifference and perimeterDifference. Both methods take a doubleradius of a second circle and return the difference from the current circle. For example, if you create a Circle object with a radius of 4 and call areaDifference(3), you will return the diffence between the area of a circle with radius 4 and the area of a circle with a radius of 3. perimeterDifferencewould be the same. Make sure you create at least one Circle and test and print the results of your methods. in javaarrow_forwardIn this exercise, you are going to build on your Circleclass from the previous exercise. You are going to add 2 method, areaDifference and perimeterDifference. Both methods take a doubleradius of a second circle and return the difference from the current circle. For example, if you create a Circle object with a radius of 4 and call areaDifference(3), you will return the diffence between the area of a circle with radius 4 and the area of a circle with a radius of 3. perimeterDifferencewould be the same. Make sure you create at least one Circle and test and print the results of your methods. given: public class Circle{private double radius;public Circle(double theRadius){radius = theRadius;}// Add a method called area that returns the area of a circle// using Math.PIpublic double area(){return Math.PI*radius*radius;}// Add a method called perimeter that returns the perimeter of a// circle using Math.PIpublic double perimeter(){return Math.PI*2*radius;}}arrow_forwardjava, PLEASE THE METHOD SHOULD USE THE INITIAL ARRAYLIST NOT TO CREATE A NEW ONE Create a class called OurArrayList and implement the following methods. Do NOT create any auxiliary memory.Include a main method and test all your methods with appropriate examples.a. Write a method called scaleByK() that takes an ArrayList of integers as aparameter and replaces every integer of value K with K copies of itself. Forexample, if the list stores the values (4, 1 , 2, 0 ,3) before the method is called, itshould store the values (4, 4, 4, 4, 1, 2, 2, 3, 3, 3) after the method finishesexecuting. Zeroes and negative numbers should be removed from the list by thismethodarrow_forward
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