Reader close() method in Java with Examples

In Java, the Reader class provides a way to read character streams. Its close() method is used to close the stream and release any associated resources.

• If the stream is open, close() closes it and releases any associated resources.
• If the stream is already closed, calling close() has no effect.
• Any read or write operation attempted after closing the stream will throw an IOException.

Syntax

public abstract void close()

• Parameters: This method does not accept any parameters
• Return Type: This method does not return any value.

Examples of close() Method

Example 1: Reading Characters and Closing the Stream

import java.io.*; class GFG {  public static void main(String[] args){  try {  String str = "GeeksForGeeks";  // Create a Reader instance  Reader reader = new StringReader(str);  int ch;  // Read the first 5 characters  for (int i = 0; i < 5; i++) {  ch = reader.read();  System.out.println(  "Integer value of character read: "  + ch);  System.out.println("Actual character read: "  + (char)ch);  }  // Close the stream  reader.close();  System.out.println("Stream Closed.");  }  catch (Exception e) {  System.out.println(e);  }  } } 

Integer value of character read: 71 Actual character read: G Integer value of character read: 101 Actual character read: e Integer value of character read: 101 Actual character read: e Integer value o...

Explanation: The first 5 characters of the string "GeeksForGeeks" are read and printed. Calling close() releases the stream resources, marking the end of the reader’s usage.

Example 2: Performing Operations After Closing the Stream

import java.io.*; class GFG{  public static void main(String[] args){  try {  String str = "GeeksForGeeks";  // Create a Reader instance  Reader reader = new StringReader(str);  // Close the stream  reader.close();  System.out.println("Stream Closed.");  // Attempt to check if the reader is ready  System.out.println(  "Is Reader ready to be read? "  + reader.ready());  }  catch (Exception e) {  System.out.println(e);  }  } } 

Stream Closed. java.io.IOException: Stream closed 

Explanation: After calling close(), any attempt to read from or interact with the stream (e.g., ready()) results in an IOException.

Why Use close()?

• Prevents resource leaks in your program.
• Ensures that files or network streams are properly released.
• Mandatory in real-world applications to avoid memory and file descriptor exhaustion.

Note: Using try-with-resources in Java automatically calls close() on streams, making code safer and cleaner.