EASYTUTORGUIDEJava • Java 26

Files and NIO.2

Chapter 35 of 60 • beginner to advanced • code example for every topic

5 topics5 code examples10 Q&A

35.1 Opening Files 35.2 Reading Data 35.3 Writing Data 35.4 Paths/Metadata 35.5 Resource and Error Handling

35.1 Opening Files

This topic teaches Opening Files as part of Files and NIO.2. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

import java.nio.file.*;
public class Main { public static void main(String[] args)throws Exception{ Path p=Path.of("demo.txt"); Files.writeString(p,"hello"); System.out.println(Files.readString(p)); } }

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 Opening Files. 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.

35.2 Reading Data

This topic teaches Reading Data as part of Files and NIO.2. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

public class Main { public static void main(String[] args) { // Reading Data
System.out.println("Java example"); } }

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 Reading Data. 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.

35.3 Writing Data

This topic teaches Writing Data as part of Files and NIO.2. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

public class Main { public static void main(String[] args) { // Writing Data
System.out.println("Java example"); } }

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 Writing Data. 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.

35.4 Paths/Metadata

This topic teaches Paths/Metadata as part of Files and NIO.2. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

public class Main { public static void main(String[] args) { // Paths/Metadata
System.out.println("Java example"); } }

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 Paths/Metadata. 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.

35.5 Resource and Error Handling

This topic teaches Resource and Error Handling as part of Files and NIO.2. Learn the purpose first, then inspect the syntax and test it with small inputs before using it in production.

Code example

public class Main { public static void main(String[] args) { // Resource and Error Handling
System.out.println("Java example"); } }

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 Resource and Error Handling. 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.