Question

Write a statement that creates an Array list object and assigns its address to a variable named 1 lards. The Array list should be able to store string objects only.

Short answer

Answer: To create an ArrayList object called 'lards' that can store elements of type String only, you would use the following code snippet: ```java import java.util.ArrayList; // Import ArrayList class ArrayList lards = new ArrayList(); // Create ArrayList object that stores string elements ```

Step-by-step solution

Import java.util.ArrayList

To work with ArrayList, we need to import it from the java.util package. In the beginning, write: ```java import java.util.ArrayList; ```

Create ArrayList object

Now, create an ArrayList object that can store String objects only. To make sure it contains only String elements, use the diamond syntax, which is : ```java ArrayList arrayList = new ArrayList(); ```

Assign the address to variable 'lards'

Finally, assign the created ArrayList's address to the variable 'lards': ```java ArrayList lards = arrayList; ``` Here is the full code: ```java import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList arrayList = new ArrayList(); // Create ArrayList object ArrayList lards = arrayList; // Assign address to variable 'lards' } } ```

Key concepts

Java programming

Java is a high-level, object-oriented programming language designed to have as few implementation dependencies as possible. Learning Java can be a rewarding experience because it's widely used in various applications, from web to mobile app development. Understanding Java is the first step in creating versatile applications, and one of the fundamental concepts to grasp is working with collections, such as 'ArrayList'.

In Java, an 'ArrayList' is a resizable array, which can dynamically grow or shrink in size as elements are added or removed, unlike regular arrays which have a fixed size. To manipulate these collections efficiently, the Java Standard Library provides a set of classes and interfaces - one of them is the 'java.util.ArrayList' class.

ArrayList object

An 'ArrayList' object in Java is essentially a container that can hold a number of objects. The capacity of an 'ArrayList' is automatically increased as objects are added to it. Since an 'ArrayList' implements the 'List' interface, it also provides methods to manipulate data, such as

• adding elements,
• removing elements,
• searching for elements, and
• iterating through the list.

When creating an 'ArrayList', the type of elements it can contain is specified using generics, which ensures type safety by allowing only one type of objects, making the code more bug-resistant.

String type storage

When we refer to 'String type storage' in an 'ArrayList' context, we are focusing on creating a collection that exclusively holds 'String' objects. 'Strings' in Java are a sequence of characters and are one of the most used data types.

In the context of an 'ArrayList', using 'String' as the type parameter, enclosed in angle brackets (< >), ensures that you can only add 'String' objects to the collection. This specificity prevents type errors at compile-time and allows developers to work with a safe, homogeneous collection of elements, simplifying operations such as sorting or searching.

java.util.ArrayList

The 'java.util.ArrayList' is a part of the Java Collections Framework and it's a popular choice when working with lists in Java. To use it in a program, one must import it using import java.util.ArrayList;. It's both flexible and powerful due to its ability to dynamically grow and shrink.

For an 'ArrayList' to be confined to a specific data type, such as 'String', Java generics are used. This can vastly decrease the likelihood of runtime errors related to typecasting. Also, the 'ArrayList' class provides numerous methods that facilitate manipulation of list elements, including

• 'add()' for adding,
• 'get()' for retrieving,
• 'set()' for replacing,
• 'remove()' for removing elements,
• and 'clear()' for emptying the list entirely.

Understanding and utilizing 'java.util.ArrayList' can significantly improve data handling and manipulation in Java programs.