CharBuffer hasArray() method in Java

Last Updated : 27 Mar 2025

The java.nio.CharBuffer contains the hasArray() function. The CharBuffer class is used to check if an accessible char array backs up the buffer that is provided. If this buffer has an accessible backing array, it returns true; otherwise, it returns false. The array() and arrayOffset() methods can be securely called since they operate on the backing array if this method returns true.

Syntax:

Return Value: If and only if this buffer is not read-only and is supported by an array, then this function will return true. If not, false is returned.

Example 1:

The code illustrates how to use Java's CharBuffer. The characters 'a' and 'b' are inserted at predetermined points in a CharBuffer that has a capacity of 12 characters. It uses the hasArray() method to determine whether the buffer is supported by an array after rewinding it to the beginning. Although they are exceptional in this situation, the code manages possible problems like ReadOnlyBufferException and IllegalArgumentException. The CharBuffer's storage array backing is verified by the hasArray() method, and the result is reported.

Implementation:

FileName: CharBufferExample1 .java

import java.io.*;
import java.nio.*; 
import java.util.*; 
public class CharBufferExample1 
{ 
	public static void main(String[] args) 
	{ 
	    // Declaring the CharBuffer's capacity 
		int cap = 12; 
		// declaring and Creating the CharBuffer 
		try 
		{ 
			// Allocating size capacity and generating 
			// an instance of Intbuffer 
			CharBuffer chabuff = CharBuffer.allocate(cap); 
		    // loading the data into the Intbuffer  
			chabuff.put('a'); 
			chabuff.put(3, 'b'); 
			chabuff.rewind(); 
			// verifying whether the CharBuffer cb is supported by an array 
			boolean arr = chabuff.hasArray(); 
			if (arr) 
				System.out.println("CharBuffer chabuff is" + " backed by the array"); 
			else
				System.out.println("CharBuffer chabuff is" + " not backed by the any array"); 
		} 
		catch (IllegalArgumentException e) { 
			System.out.println("IllegalArgumentException catched"); 
		} 
		catch (ReadOnlyBufferException e) { 
			System.out.println("ReadOnlyBufferException catched"); 
		} 
	} 
}   

Output:

 
CharBuffer chabuff is backed by the array

Example 2:

The code illustrates how to create and use a CharBuffer in Java. It starts by initializing a 12-character CharBuffer and fills it with the characters "a" and "b" at certain locations. It uses asReadOnlyBuffer() to make a read-only copy of the buffer after it has been rewound. The hasArray() function prints the result after determining whether this read-only buffer is supported by an array. The method also manages errors such as ReadOnlyBufferException and IllegalArgumentException, although the latter is rare in this case because buffer operations are expected.

Implementation:

FileName: CharBufferExample2.java

import java.nio.*; 
import java.util.*; 
import java.io.*;
public class CharBufferExample2 
{ 
	public static void main(String[] args) 
	{ 
		// Declaring the CharBuffer's capacity 
		int cap = 12; 
		// Creating and declaring the CharBuffer 
		try { 
			// Allocating size capacity and constructing
			// an instance of CharBuffer 
			CharBuffer charbuff = CharBuffer.allocate(cap); 
			// adding the value to the CharBuffer 
			charbuff.put('a'); 
			charbuff.put(3, 'b'); 
			charbuff.rewind(); 
			// utilizing the asReadOnlyBuffer() method to 
			//Create a read-only duplicate of CharBuffer 
			CharBuffer charbuff1 = charbuff.asReadOnlyBuffer(); 
		    // verifying whether the CharBuffer cb can be used by an array 
			boolean isArray = charbuff1.hasArray(); 
			if (isArray) 
				System.out.println("CharBuffer charbuff is" + " backed by the array"); 
			else
				System.out.println("CharBuffer charbuff is" + " not backed by the any array"); 
		} 
		catch (IllegalArgumentException ex) { 
			System.out.println("IllegalArgumentException catched"); 
		} 
		catch (ReadOnlyBufferException ex) { 
			System.out.println("ReadOnlyBufferException catched"); 
		} 
	} 
}   

Output:

 
CharBuffer charbuff is not backed by the any array

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