// Import the required package import java.io.*; // Create an output stream to write to a file OutputStream outputStream = new FileOutputStream("example.txt"); DataOutputStream dataOutputStream = new DataOutputStream(outputStream); // Write a char to the output stream char ch = 'a'; dataOutputStream.writeChar(ch); // Close the output stream dataOutputStream.close();Description of Example: In this example, we first import the java.io package to access the required classes. We then create an output stream to write to a file using the FileOutputStream class. Next, we create a DataOutputStream object and pass the output stream as its argument. This allows us to use the writeChar() method to write a Unicode character to the output stream. In this case, we write the character 'a'. Finally, we close the output stream using the close() method. Package Library: The writeChar() method is part of the java.io package, which is included in the Java Standard Library.