EASYTUTORGUIDEJava • Java 26

List, Set, Map, Queue, and Deque

Chapter 27 of 60 • beginner to advanced • code example for every topic

5 topics5 code examples10 Q&A

27.1 List, Set, Map, Queue, and Deque Fundamentals 27.2 List, Set, Map, Queue, and Deque Syntax and Structure 27.3 List, Set, Map, Queue, and Deque Practical Example 27.4 List, Set, Map, Queue, and Deque Common Mistakes 27.5 List, Set, Map, Queue, and Deque Best Practices

27.1 List, Set, Map, Queue, and Deque Fundamentals

This topic teaches List, Set, Map, Queue, and Deque Fundamentals as part of List, Set, Map, Queue, and Deque. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

import java.util.*;
public class Main { public static void main(String[] args){ List<Integer> xs=new ArrayList<>(List.of(3,1,2)); Collections.sort(xs); System.out.println(xs); } }

Step-by-step explanation

Identify the values, objects, tables, or resources used by the example.
Read each statement in execution order.
Predict what the program or query should produce.
Run it in a safe local/test environment.
Change one input and explain the new result.

Expected output/result

You should see a small result that demonstrates List, Set, Map, Queue, and Deque Fundamentals. Exact formatting can differ by runtime, client, database state, operating system, or tool version.

Common mistakes

Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.

Practice exercise

Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.

27.2 List, Set, Map, Queue, and Deque Syntax and Structure

This topic teaches List, Set, Map, Queue, and Deque Syntax and Structure as part of List, Set, Map, Queue, and Deque. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

import java.util.*;
public class Main { public static void main(String[] args){ List<Integer> xs=new ArrayList<>(List.of(3,1,2)); Collections.sort(xs); System.out.println(xs); } }

Step-by-step explanation

Identify the values, objects, tables, or resources used by the example.
Read each statement in execution order.
Predict what the program or query should produce.
Run it in a safe local/test environment.
Change one input and explain the new result.

Expected output/result

You should see a small result that demonstrates List, Set, Map, Queue, and Deque Syntax and Structure. Exact formatting can differ by runtime, client, database state, operating system, or tool version.

Common mistakes

Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.

Practice exercise

Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.

27.3 List, Set, Map, Queue, and Deque Practical Example

This topic teaches List, Set, Map, Queue, and Deque Practical Example as part of List, Set, Map, Queue, and Deque. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

import java.util.*;
public class Main { public static void main(String[] args){ List<Integer> xs=new ArrayList<>(List.of(3,1,2)); Collections.sort(xs); System.out.println(xs); } }

Step-by-step explanation

Identify the values, objects, tables, or resources used by the example.
Read each statement in execution order.
Predict what the program or query should produce.
Run it in a safe local/test environment.
Change one input and explain the new result.

Expected output/result

You should see a small result that demonstrates List, Set, Map, Queue, and Deque Practical Example. Exact formatting can differ by runtime, client, database state, operating system, or tool version.

Common mistakes

Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.

Practice exercise

Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.

27.4 List, Set, Map, Queue, and Deque Common Mistakes

This topic teaches List, Set, Map, Queue, and Deque Common Mistakes as part of List, Set, Map, Queue, and Deque. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

import java.util.*;
public class Main { public static void main(String[] args){ List<Integer> xs=new ArrayList<>(List.of(3,1,2)); Collections.sort(xs); System.out.println(xs); } }

Step-by-step explanation

Identify the values, objects, tables, or resources used by the example.
Read each statement in execution order.
Predict what the program or query should produce.
Run it in a safe local/test environment.
Change one input and explain the new result.

Expected output/result

You should see a small result that demonstrates List, Set, Map, Queue, and Deque Common Mistakes. Exact formatting can differ by runtime, client, database state, operating system, or tool version.

Common mistakes

Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.

Practice exercise

Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.

27.5 List, Set, Map, Queue, and Deque Best Practices

This topic teaches List, Set, Map, Queue, and Deque Best Practices as part of List, Set, Map, Queue, and Deque. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

import java.util.*;
public class Main { public static void main(String[] args){ List<Integer> xs=new ArrayList<>(List.of(3,1,2)); Collections.sort(xs); System.out.println(xs); } }

Step-by-step explanation

Identify the values, objects, tables, or resources used by the example.
Read each statement in execution order.
Predict what the program or query should produce.
Run it in a safe local/test environment.
Change one input and explain the new result.

Expected output/result

You should see a small result that demonstrates List, Set, Map, Queue, and Deque Best Practices. Exact formatting can differ by runtime, client, database state, operating system, or tool version.

Common mistakes

Watch for invalid input, unchecked errors, incorrect type assumptions, missing cleanup, unsafe permissions, injection risks, or code/query logic that handles only the happy path.

Practice exercise

Rebuild this example with your own data. Add one edge case, predict the result before running it, and explain why the final result is correct.