Java NIO Complete Tutorial(With Examples)

In this comprehensive tutorial, we will learn Java NIO to build high-performance, I/O-intensive applications. 

You’ll start by understanding the foundation of Java NIO, including its architecture, key concepts, and importance in modern programming. 

As you progress, you’ll explore working with channels, paths, and files, and learn how to perform file I/O operations, network I/O operations, and buffer management. 

With code snippets and real-world examples, this tutorial will equip you with the skills to master Java NIO and take your application development to the next level.

Java NIO Architecture

The foundation of Java NIO (Non-blocking I/O) lies in its architecture, key concepts, and understanding of blocking and non-blocking I/O. 

The Java NIO API is built around the concept of channels and buffers. 

Channels represent connections to entities capable of performing I/O operations, such as files, sockets, and datagram sockets. 

Buffers, on the other hand, are containers that hold data to be written or read from channels. 

Here’s a simple diagram to illustrate the relationship between channels and buffers:

There are several types of channels, including:

• FileChannel: for reading and writing files
• SocketChannel: for TCP communication
• ServerSocketChannel: for accepting incoming connections
• DatagramChannel: for UDP communication

All these are discussed in great detail later.

Buffers, on the other hand, are containers that hold data to be written or read from channels. 

There are several types of buffers, including:

• ByteBuffer
• CharBuffer
• ShortBuffer
• IntBuffer
• LongBuffer
• FloatBuffer
• DoubleBuffer

Channels

A Channel represents a connection to an entity capable of performing I/O operations, such as a file, socket, or pipe. 

You can think of a Channel as a pipe through which data flows. 

In Java NIO, Channels are instances of the java.nio.channels.Channel interface. 

When working with channels, you’ll typically use one of two primary methods: read() and write(). 

The read() method reads data from a channel into a buffer, while the write() method writes data from a buffer to a channel.

There are several types of channels, each designed for a specific purpose. These include:

• FileChannel: used for reading and writing files
• SocketChannel: used for TCP network communication
• ServerSocketChannel: used for accepting incoming TCP connections
• DatagramChannel: used for UDP network communication

To create a channel, you typically invoke a static factory method or a constructor that returns a channel instance.

Knowing which type of channel to use depends on your specific use case and the requirements of your application. 

For example, if you need to read and write files, FileChannel is the way to go. 

If you need to establish a TCP connection with a remote server, SocketChannel is the correct choice.

A. FileChannel

FileChannel is a channel that reads, writes, maps, and manipulates a file. 

It is a blocking API, meaning that it will block until the operation is complete. 

You can think of it as a stream-based API, where you can read or write data in a sequential manner.

Here’s an example of how you can create a FileChannel:

FileChannel channel = FileChannel.open(Paths.get("example.txt"), 
                                       StandardOpenOption.READ, 
                                       StandardOpenOption.WRITE);

In this example, you open a file using the FileChannel.open() method, specifying the file path and the StandardOpenOption.READ option. 

To create a FileChannel, you can also use the FileInputStream or FileOutputStream classes, which have methods that return a FileChannel object:

FileInputStream fis = new FileInputStream("example.txt"); 
FileChannel fileChannel = fis.getChannel();

You then allocate a ByteBuffer to store the read data and use a loop to read the file channel until there is no more data to read. 

Finally, you close the file channel to release system resources.

Here’s an example of reading data from a file using a FileChannel:

FileInputStream fileInputStream = new FileInputStream("example.txt"); 
FileChannel fileChannel = fileInputStream.getChannel(); 
ByteBuffer buffer = ByteBuffer.allocate(1024); 
int bytesRead = fileChannel.read(buffer); 
while (bytesRead!= -1) { 
  buffer.flip(); 
  while (buffer.hasRemaining()) { 
    System.out.print((char) buffer.get()); 
  } 
  buffer.clear(); 
  bytesRead = fileChannel.read(buffer); 
}

In this example, you create a FileChannel from a FileInputStream, allocate a ByteBuffer to hold the data, and then read from the channel into the buffer using the read() method. 

You then flip the buffer to prepare it for reading, print out the contents, and clear the buffer to prepare it for the next read operation.

Similarly, you can write data to a file using the write() method of the FileChannel class:

import java.io.IOException; 
import java.nio.channels.FileChannel; 
import java.nio.file.Paths; 
import java.nio.file.StandardOpenOption; 

public class WriteFileExample { 
  public static void main(String[] args) throws IOException { 
    FileChannel fileChannel = FileChannel.open(Paths.get("example.txt"), 
                                               StandardOpenOption.WRITE, 
                                               StandardOpenOption.CREATE); 
    ByteBuffer buffer = ByteBuffer.wrap("Hello, World!".getBytes()); 
    while (buffer.hasRemaining()) { 
      fileChannel.write(buffer); 
    } 
    fileChannel.close(); 
  } 
}

In this example, you open a file using the FileChannel.open() method, specifying the file path, the StandardOpenOption.WRITE option, and the StandardOpenOption.CREATE option to create the file if it does not exist. 

You then allocate a ByteBuffer to store the write data and use a loop to write the data to the file channel until there is no more data to write. 

Finally, you close the file channel to release system resources.

B. SocketChannel

SocketChannel is a fundamental component of the NIO API that enables you to establish TCP connections and exchange data between clients and servers.

When working with SocketChannel, you’ll typically create a client-server architecture where the server listens for incoming connections and the client initiates a connection to the server. 

To create a SocketChannel, you’ll need to use the open() method of the SocketChannel class, which returns a new SocketChannel object.

SocketChannel socketChannel = SocketChannel.open();

Once you have a SocketChannel object, you can configure it to connect to a remote server using the connect() method.

This method takes an endpoint represented by a SocketAddress object as an argument.

SocketAddress socketAddress = new InetSocketAddress("localhost", 8080); 
socketChannel.connect(socketAddress);

After establishing a connection, you can use the read() and write() methods to exchange data between the client and server.

These methods operate on ByteBuffer objects, which serve as containers for the data being transmitted.

ByteBuffer buffer = ByteBuffer.allocate(1024); 
int bytesRead = socketChannel.read(buffer);

In this example, the read() method reads data from the SocketChannel into the ByteBuffer, and the bytesRead variable stores the number of bytes read.

You can then process the data in the buffer as needed.

Below is a complete example of how to create a SocketChannel and connect to a remote server:

// Create a SocketChannel 
SocketChannel socketChannel = SocketChannel.open(); 
// Connect to a remote server 
socketChannel.connect(new InetSocketAddress("example.com", 80)); 
// Check if the connection is established 
boolean isConnected = socketChannel.isConnected(); 
System.out.println("Connected: " + isConnected); 
// Read and write data using the channel 
ByteBuffer buffer = ByteBuffer.allocate(1024); 
int bytesRead = socketChannel.read(buffer); 
System.out.println("Bytes read: " + bytesRead); 
// Write data to the channel 
buffer.flip(); 
socketChannel.write(buffer);

C. ServerSocketChannel

On the server-side, you’ll use a ServerSocketChannel to listen for incoming connections.

To create a ServerSocketChannel, you need to use the static open() method of the ServerSocketChannel class

Next, you need to bind the ServerSocketChannel to a specific address and port using the bind() method.

In this example, the ServerSocketChannel is bound to the localhost address and port 8080.

To accept an incoming connection, you can use the accept() method, which returns a SocketChannel object representing the accepted connection.

Once you have a SocketChannel object, you can read and write data to the client using the read() and write() methods, respectively.

Here’s an example of how to create a ServerSocketChannel and accept a connection:

// Create a ServerSocketChannel 
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open(); 
// Bind the channel to a local address 
serverSocketChannel.bind(new InetSocketAddress("localhost", 8080)); 
// Accept an incoming connection 
SocketChannel socketChannel = serverSocketChannel.accept(); 
System.out.println("Incoming connection accepted"); 
// Read and write data using the channel 
ByteBuffer buffer = ByteBuffer.allocate(1024); 
int bytesRead = socketChannel.read(buffer); 
System.out.println("Bytes read: " + bytesRead); 
// Write data to the channel 
buffer.flip(); 
socketChannel.write(buffer);

Now, your application is ready to accept incoming connections.

In this example, the server accepts incoming connections, reads data from the client, and writes it back to the client.

Note that this is a very basic implementation, and in a real-world scenario, you would need to handle errors, manage multiple connections, and implement additional logic to handle client requests.

D. DatagramChannel

When working with UDP communication, you need a channel that can send and receive datagrams.

That’s where DatagramChannel comes in.

This channel is used for connectionless communication, meaning that there’s no guarantee of delivery or order of packets.

You’re responsible for handling errors and packet loss.

To create a DatagramChannel, you can use the open() method of the DatagramChannel class:

DatagramChannel channel = DatagramChannel.open();

By default, the channel is blocking, but you can configure it to be non-blocking by setting the blocking mode to false.

channel.configureBlocking(false);

To send a datagram, you need to create a ByteBuffer containing the data you want to send, and then use the send() method

ByteBuffer buffer = ByteBuffer.allocate(1024); 
buffer.put("Hello, UDP!".getBytes()); 
buffer.flip(); 
channel.send(buffer, new InetSocketAddress("localhost", 8080));

To receive a datagram, you can use the receive() method, which returns the number of bytes received:

ByteBuffer buffer = ByteBuffer.allocate(1024); 
int bytesRead = channel.receive(buffer);

Here’s a complete example of using a DatagramChannel

// Create a DatagramChannel 
DatagramChannel datagramChannel = DatagramChannel.open(); 
// Send a datagram to a remote server 
ByteBuffer buffer = ByteBuffer.allocate(1024); 
buffer.put("Hello, server!".getBytes()); 
buffer.flip(); 
datagramChannel.send(buffer, new InetSocketAddress("example.com", 8080)); 
System.out.println("Datagram sent"); 
// Receive a datagram from a remote server 
buffer.clear(); 
SocketAddress address = datagramChannel.receive(buffer); 
System.out.println("Datagram received from " + address);

Blocking and Non-Blocking I/O

In traditional blocking I/O, when you read or write data to a channel, your thread is blocked until the operation is complete. 

This means that your program will wait until the data is fully read or written before proceeding to the next instruction. 

For example, consider the following code snippet:

FileChannel channel = new FileInputStream("example.txt").getChannel();  
ByteBuffer buffer = ByteBuffer.allocate(1024); 
channel.read(buffer);

In this example, the read() method will block until the data is fully read from the file. 

This can lead to performance bottlenecks, especially in applications that require concurrent I/O operations.

On the other hand, non-blocking I/O allows your program to continue executing without waiting for the I/O operation to complete. 

In Java NIO, this is achieved through the use of channels and buffers. 

When you perform a non-blocking read or write operation, the channel returns immediately, and your program can continue executing other tasks. 

The data is stored in a buffer, which can be processed later.

For instance, consider the following code snippet:

SocketChannel channel = SocketChannel.open(); 
ByteBuffer buffer = ByteBuffer.allocate(1024); 
int bytesRead = channel.read(buffer);

In this example, the read() method will return immediately, and the bytesRead variable will contain the number of bytes read from the socket. 

Your program can then process the data in the buffer while the channel continues to receive data in the background.

So, why is non-blocking I/O important in Java NIO? 

By allowing your program to continue executing without waiting for I/O operations to complete, you can significantly improve performance and responsiveness in your applications. 

Additionally, non-blocking I/O enables you to handle multiple channels concurrently, making it ideal for high-performance network servers and real-time data processing applications.

Paths and Files

Many of the I/O operations you perform in Java NIO involve working with files and directories. 

To do this effectively, you need to understand how to create and manipulate paths, as well as how to use the Files class for file operations.

In Java NIO, a path is represented by the Path interface, which is located in the java.nio.file package. 

A Path object represents a file system path, which can be a directory or a file. 

You can create a Path object using the Paths class, which provides several methods for creating paths from strings, URIs, and other sources.

Here’s an example of how you can create a Path object from a string:

Path path = Paths.get("path/to/file.txt");

You can also use the Path.of() method, which is a more concise way of creating a Path object.

Path path = Path.of("path/to/your/file.txt");

Once you have a Path object, you can perform various operations on it, such as checking if the file exists, getting the file name, or resolving the path against a parent path.

For example, you can use the isRegularFile() method to check if the path represents a regular file.

if (path.isRegularFile()) { 
  System.out.println("The path represents a regular file."); 
}

You can also use the getFileName() method to get the file name of the path.

Path fileName = path.getFileName(); 
System.out.println("The file name is " + fileName);

In addition to these methods, the Path interface provides many other useful methods for manipulating paths, such as resolving the path against a parent path, normalizing the path, and more.

You can also use the resolve() method to combine two paths:

Path basePath = Paths.get("/home/user"); 
Path filePath = basePath.resolve("file.txt");

In addition to creating paths, you can also manipulate them using various methods provided by the Path interface. 

For example, you can get the parent directory of a path using the getParent() method:

Path parentDir = path.getParent();

Or you can get the file name of a path using the getFileName() method:

Path fileName = path.getFileName();

Files class

To perform various file operations in Java NIO, you can use the Files class, which provides a convenient way to work with files and directories.

 This class is part of the java.nio.file package and offers a range of methods for tasks such as creating, deleting, copying, and moving files, as well as checking file attributes and permissions.

One of the most common file operations is reading and writing files. 

Reading Files

The Files class provides several methods for reading files, such as readAllBytes(), readAllLines() and newBufferedReader(). 

For example, to read the contents of a file into a byte array, you can use the readAllBytes() method:

Path filePath = Paths.get("path/to/file.txt"); 
byte[] fileContent = Files.readAllBytes(filePath);

In this example, we first create a Path object representing the file we want to read. 

Then, we call the readAllBytes() method, passing the Path object as an argument. 

The method returns a byte array containing the contents of the file.

Similarly, you can use readAllLines() method to read the contents of a file into a list of strings, where each string represents a line in the file:

Path filePath = Paths.get("path/to/your/file.txt"); 
List fileLines = Files.readAllLines(filePath);

You can use the newBufferedReader() method to read a file line by line:

Path filePath = Paths.get("path/to/your/file.txt"); 
try (BufferedReader reader = Files.newBufferedReader(filePath)) { 
  String line; 
  while ((line = reader.readLine())!= null) { 
    System.out.println(line); 
  } 
}

In this example, we create a BufferedReader object using the newBufferedReader() method. 

Then, we read the file line by line using a while loop, printing each line to the console.

Writing Files

Similarly, to write a string to a file, you can use the write() method:

Path filePath = Paths.get("path/to/file.txt"); 
String fileContent = "Hello, World!"; 
Files.write(filePath, fileContent.getBytes());

// write multiple lines at once
List lines = Arrays.asList("Line 1", "Line 2", "Line 3"); 
Files.write(path, lines);

In this example, we create a byte array containing the content we want to write to the file. 

Then, we call the write() method, passing the Path object and the byte array as arguments. The method writes the content to the file.

Similarly, you can use the newBufferedWriter() method to write a file line by line:

Path filePath = Paths.get("path/to/your/file.txt"); 
try (BufferedWriter writer = Files.newBufferedWriter(filePath)) { 
  writer.write("This is the first line"); 
  writer.newLine(); 
  writer.write("This is the second line"); 
}

In this example, we create a BufferedWriter object using the newBufferedWriter() method. 

Then, we write two lines to the file using the write() and newLine() methods.

Creating & Deleting Files

In addition to reading and writing files, the Files class also provides methods for creating and deleting files and directories. 

For example, to create a new directory, you can use the createDirectory() method:

Path dirPath = Paths.get("path/to/new/dir"); 
Files.createDirectory(dirPath);

To delete a file or directory, you can use the delete() method:

Path filePath = Paths.get("path/to/file.txt"); 
Files.delete(filePath);

Files class also provides methods for checking file attributes and permissions, such as isReadable(), isWritable() and isExecutable(). 

For example, to check if a file is readable, you can use the isReadable() method:

Path filePath = Paths.get("path/to/file.txt"); 
if (Files.isReadable(filePath)) { 
  System.out.println("The file is readable."); 
} else { 
  System.out.println("The file is not readable."); 
}

By using the Files class, you can perform various file operations in a concise and efficient manner, making it a valuable tool in your Java NIO toolkit.

Using Scatter/Gather I/O for efficient data transfer

Your application requires efficient data transfer between a channel and a set of buffers. 

This is where Scatter/Gather I/O comes into play. 
Scatter/Gather I/O is a mechanism that allows you to read from or write to a channel using multiple buffers. 

This approach is particularly useful when you need to transfer large amounts of data, as it reduces the number of system calls and improves overall performance.

Let’s look at an example to illustrate how Scatter/Gather I/O works. 

Suppose you want to read data from a file channel into multiple buffers. You can use the read() method of the FileChannel class, passing an array of buffers as an argument:

ByteBuffer header = ByteBuffer.allocate(10); 
ByteBuffer body = ByteBuffer.allocate(1024); 
ByteBuffer footer = ByteBuffer.allocate(10); 
ByteBuffer[] buffers = { header, body, footer }; 
FileChannel channel = new FileInputStream("example.txt").getChannel(); 
channel.read(buffers);

In this example, the read() method reads data from the file channel into the three buffers: header, body and footer. 

The data is scattered across the buffers, hence the term “scatter” I/O.

Conversely, you can use the write() method to write data from multiple buffers to a channel:

ByteBuffer header = ByteBuffer.allocate(10); 
ByteBuffer body = ByteBuffer.allocate(1024); 
ByteBuffer footer = ByteBuffer.allocate(10); 
ByteBuffer[] buffers = { header, body, footer }; 
FileChannel channel = new FileOutputStream("example.txt").getChannel(); 
channel.write(buffers);

In this case, the write()method gathers data from the three buffers and writes it to the file channel.

Scatter/Gather I/O provides several benefits, including improved performance, reduced system calls, and increased flexibility in handling complex data structures. 

By using multiple buffers, you can optimize your data transfer operations and make your application more efficient.

File Locking

File locking is necessary, especially when you’re working with files in a single-threaded environment. 

However, in a multi-threaded or multi-process environment, file locking becomes vital to ensure data consistency and integrity.

In Java NIO, file locking is achieved using the FileLock class, which provides a way to lock a region of a file or the entire file. 

You can acquire a file lock by calling the lock() method of the FileChannel class, which returns a FileLock object. 

Here’s an example:

FileChannel channel = FileChannel.open(Paths.get("example.txt"), 
                                       StandardOpenOption.READ, 
                                       StandardOpenOption.WRITE); 
FileLock lock = channel.lock();

In this example, the lock() method attempts to acquire an exclusive lock on the entire file. 

If the lock is acquired successfully, the FileLock object is returned. 

You can then use the lock() object to release the lock when you’re done with the file.

File locking is important because it prevents other threads or processes from accessing the file while you’re modifying it. 

Imagine a scenario where multiple threads are writing to the same file simultaneously. 

Without file locking, the file contents would become corrupted, leading to data inconsistencies. 

By acquiring a file lock, you ensure that only one thread or process can modify the file at a time, maintaining data integrity.

Java NIO provides two types of file locks: exclusive and shared. 

An exclusive lock, as shown in the example above, allows only one thread or process to access the file. 

A shared lock, on the other hand, allows multiple threads or processes to access the file simultaneously, but only for reading. 

You can acquire a shared lock by calling the lock(0, Long.MAX_VALUE, true) method, where the third argument specifies that the lock is shared.

Selector and Selection Keys

A selector is an object that can be used to multiplex multiple channels, allowing you to perform I/O operations on multiple channels simultaneously. 

This is particularly useful in network programming, where you may need to handle multiple connections concurrently. 

A selector is created using the Selector.open() method:

Selector selector = Selector.open();

Once you have a selector, you can register one or more channels with it using the SelectableChannel.register() method. 

The register() method returns a SelectionKey, which represents the registration of a channel with a Selector.

It contains information about the channel, the operations that are ready to be performed, and the selector itself.

Selection Keys have four operations that can be specified when registering a Channel:

• OP_READ: The Channel is ready for reading.
• OP_WRITE: The Channel is ready for writing.
• OP_CONNECT: The Channel is ready to connect.
• OP_ACCEPT: The Channel is ready to accept incoming connections.

You can specify one or more of these operations when registering a Channel, depending on the type of I/O operation you want to perform.

Example:

ServerSocketChannel serverChannel = ServerSocketChannel.open(); 
serverChannel.configureBlocking(false); 
SelectionKey key = serverChannel.register(selector, 
                                          SelectionKey.OP_ACCEPT);

In this example, we’re registering a server socket channel with the selector, indicating that we’re interested in accepting incoming connections (represented by the OP_ACCEPT operation).

You can retrieve the selection key using the SelectableChannel.keyFor() method:

SelectionKey key = serverChannel.keyFor(selector);

When you’re ready to perform I/O operations, you can use the selector to select the channels that are ready for the desired operations. 

This is done using the Selector.select() method:

select() method returns the number of selection keys that are ready for the desired operations. 

You can then iterate over the selected keys using the Selector.selectedKeys() method:

selector.select(); 
Set selectedKeys = selector.selectedKeys(); 
// Iterate over the selected keys
Iterator iterator = selectedKeys.iterator(); 
while (iterator.hasNext()) { 
  SelectionKey key = iterator.next(); 
  if (key.isAcceptable()) { 
    // Accept an incoming connection 
  } else if (key.isReadable()) { 
    // Read data from a channel 
  } 
  iterator.remove(); 
}

In this example, you call the select() method to wait for incoming events. 

The selectedKeys() method returns a set of SelectionKeys that represent the channels that have pending events. 

You can then iterate over these keys and perform the necessary operations z(e.g., accepting incoming connections or reading data).

Buffer Management

A buffer is importantly a container that holds data, and it’s used to transfer data between channels and your application. 

Java NIO provides several types of buffers, each designed to handle specific data types. These include:

• ByteBuffer
  This is the most versatile buffer type, capable of holding raw binary data. 
  It’s often used for I/O operations involving files, sockets, and channels.
• CharBuffer
  As the name suggests, this buffer is designed to hold character data. 
  It’s commonly used for text-based I/O operations, such as reading and writing text files.
• ShortBuffer, IntBuffer, LongBuffer
  These buffers are designed to hold short, integer, and long integer data, respectively. 
  They’re often used for numerical computations and data processing.
• FloatBuffer, DoubleBuffer
  These buffers are designed to hold floating-point and double-precision floating-point data, respectively. 
  They’re commonly used for scientific and engineering applications.

To create a buffer, you can use the allocate() method, which returns a buffer of the specified capacity:

ByteBuffer buffer = ByteBuffer.allocate(1024);

In this example, allocate() is a static method that returns a new ByteBuffer instance with the specified capacity of 1024 bytes. 

You can also create a buffer from an existing array using the wrap() method

byte[] array = new byte[1024]; 
ByteBuffer buffer = ByteBuffer.wrap(array);

.You can also use the allocateDirect() method to allocate a direct buffer, which is a buffer that uses native memory instead of JVM heap memory. 

Direct buffers are more efficient for I/O operations, but they require more memory and can be slower to allocate.

To manage buffers, you need to keep track of the buffer’s position, limit, and capacity. 

The position represents the current index in the buffer, the limit represents the maximum index that you can read or write, and the capacity represents the maximum amount of data that the buffer can hold. 

Here’s an example of how you can manipulate the position and limit of a buffer:

// set the position to 10
buffer.position(10);
// set the limit to 50 
buffer.limit(50); 

In this example, you’re setting the position to 10 and the limit to 50, which means that you can read or write data between indices 10 and 50. 

You can also use the flip(), rewind()and clear() methods to manipulate the buffer’s position and limit.

Another important aspect of buffer management is dealing with buffer overflow and underflow. 

When you try to write more data than the buffer’s capacity, you’ll get a BufferOverflowException. 

Similarly, when you try to read more data than the buffer’s remaining capacity, you’ll get a BufferUnderflowException. 

To avoid these exceptions, you need to check the buffer’s remaining capacity before performing I/O operations.

Best Practices and Use Cases

All Java NIO applications require careful consideration of performance, scalability, and reliability. 

As you’ve learned throughout this tutorial, Java NIO provides a powerful set of APIs for building high-performance I/O-intensive applications. 

In this section, we’ll explore best practices for using Java NIO in real-world applications and discuss some common use cases.

When designing your Java NIO-based application, you should keep the following best practices in mind:

1. Use direct buffers wisely.
   Direct buffers can improve performance by reducing the number of memory copies, but they can also lead to increased garbage collection pauses if not managed properly. 
   You should use direct buffers only when necessary and ensure that you’re reusing them whenever possible.
2. Choose the right channel type.
   Java NIO provides different types of channels, each optimized for specific use cases. 
   For example, if you need to perform asynchronous I/O operations, you should use asynchronous channels like AsynchronousSocketChannel or AsynchronousServerSocketChannel.
3. Handle exceptions and errors correctly.
   Java NIO operations can throw various exceptions, such as IOException, ClosedChannelException or AsynchronousCloseException. 
   You should catch and handle these exceptions properly to ensure that your application remains stable and responsive.

Java NIO Use Cases

In terms of use cases, Java NIO is particularly well-suited for building high-performance I/O-intensive applications, such as:

Building a high-performance web server

Java NIO’s asynchronous I/O capabilities make it an ideal choice for building high-performance web servers that can handle a large number of concurrent connections.

Creating a real-time data processing pipeline 

Java NIO’s support for scatter/gather I/O and asynchronous operations enables you to build high-throughput data processing pipelines that can handle large volumes of data in real-time.

Developing a scalable networked application

Java NIO’s support for non-blocking I/O and asynchronous operations makes it an excellent choice for building scalable networked applications that require low latency and high throughput.

By following these best practices and understanding the use cases, you can unlock the full potential of Java NIO and build high-performance, scalable, and reliable I/O-intensive applications.

Summing up

In this article, we learned how to work with channels, paths, and files, as well as perform file and network I/O operations efficiently. 

Additionally, we grasped the importance of selectors, selection keys, and buffer management. 
With this comprehensive tutorial, you’re can now build high-performance I/O-intensive applications, following best practices and considering real-world use cases.