OpenJDK 27 · java.io.ByteArrayOutputStream · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
protected byte[]	buf The buffer where data is stored.
protected int	count The number of valid bytes in the buffer.

Access	Constructor and Description
public	ByteArrayOutputStream() Creates a new `ByteArrayOutputStream`.
public	ByteArrayOutputStream(int the initial size. size) Creates a new `ByteArrayOutputStream`, with a buffer capacity of the specified size, in bytes.

Method Summary

Modifier and Type	Method and Description
public void	close() Overrides java.io.OutputStream.close. Implements java.io.Closeable.close. Closing a `ByteArrayOutputStream` has no effect.
private void	ensureCapacity(int the desired minimum capacity. minCapacity) Increases the capacity if necessary to ensure that it can hold at least the number of elements specified by the minimum capacity argument.
public synchronized void	reset() Resets the `count` field of this `ByteArrayOutputStream` to zero, so that all currently accumulated output in the output stream is discarded.
public synchronized int	Returns: the value of the `count` field, which is the number of valid bytes in this output stream. size() Returns the current size of the buffer.
public synchronized byte[]	Returns: the current contents of this output stream, as a byte array. toByteArray() Creates a newly allocated byte array.
public synchronized String	Returns: String decoded from the buffer's contents. toString() Overrides java.lang.Object.toString. Converts the buffer's contents into a string decoding bytes using the default charset.
public synchronized String	Returns: String decoded from the buffer's contents. toString(String the name of a supported `charset` charsetName) Converts the buffer's contents into a string by decoding the bytes using the named `charset`.
public synchronized String	Returns: String decoded from the buffer's contents. toString(Charset the charset to be used to decode the `bytes` charset) Converts the buffer's contents into a string by decoding the bytes using the specified `charset`.
public synchronized String	Returns: the current contents of the output stream, as a string. toString(int the high byte of each resulting Unicode character. hibyte) Deprecated This method does not properly convert bytes into characters. Creates a newly allocated string.
public synchronized void	write(int the byte to be written. b) Implements abstract java.io.OutputStream.write. Writes the specified byte to this `ByteArrayOutputStream`.
public synchronized void	write(byte[] b, int off, int len) Overrides java.io.OutputStream.write. Writes `len` bytes from the specified byte array starting at offset `off` to this `ByteArrayOutputStream`.
public void	writeBytes(byte[] the data. b) Writes the complete contents of the specified byte array to this `ByteArrayOutputStream`.
public synchronized void	writeTo(OutputStream the output stream to which to write the data. out) Writes the complete contents of this `ByteArrayOutputStream` to the specified output stream argument, as if by calling the output stream's write method using `out.write(buf, 0, count)`.

Inherited from java.io.OutputStream:: flush nullOutputStream write

buf	back to summary
protected byte[] buf The buffer where data is stored.

count	back to summary
protected int count The number of valid bytes in the buffer.

ByteArrayOutputStream	back to summary
public ByteArrayOutputStream() Creates a new `ByteArrayOutputStream`. The buffer capacity is initially 32 bytes, though its size increases if necessary.

ByteArrayOutputStream	back to summary
public ByteArrayOutputStream(int size) Creates a new `ByteArrayOutputStream`, with a buffer capacity of the specified size, in bytes. Parameters size:int the initial size. Exceptions IllegalArgumentException: if size is negative.

Method Detail

close back to summary

close	back to summary
public void close() throws IOException Overrides java.io.OutputStream.close. Implements java.io.Closeable.close. Closing a `ByteArrayOutputStream` has no effect. The methods in this class can be called after the stream has been closed without generating an `IOException`. Annotations @Override Exceptions IOException: Doc from java.io.OutputStream.close. if an I/O error occurs.

public void close() throws IOException

Overrides java.io.OutputStream.close.

Implements java.io.Closeable.close.

Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

Annotations

@Override

Exceptions

IOException:

Doc from java.io.OutputStream.close.

if an I/O error occurs.

ensureCapacity back to summary

ensureCapacity	back to summary
private void ensureCapacity(int minCapacity) Increases the capacity if necessary to ensure that it can hold at least the number of elements specified by the minimum capacity argument. Parameters minCapacity:int the desired minimum capacity. Exceptions OutOfMemoryError: if `minCapacity < 0` and `minCapacity - buf.length > 0`. This is interpreted as a request for the unsatisfiably large capacity. `(long) Integer.MAX_VALUE + (minCapacity - Integer.MAX_VALUE)`.

private void ensureCapacity(int minCapacity)

Increases the capacity if necessary to ensure that it can hold at least the number of elements specified by the minimum capacity argument.

Parameters

minCapacity:int: the desired minimum capacity.

Exceptions

OutOfMemoryError:: if minCapacity < 0 and minCapacity - buf.length > 0. This is interpreted as a request for the unsatisfiably large capacity. (long) Integer.MAX_VALUE + (minCapacity - Integer.MAX_VALUE).

reset back to summary

reset	back to summary
public synchronized void reset() Resets the `count` field of this `ByteArrayOutputStream` to zero, so that all currently accumulated output in the output stream is discarded. The output stream can be used again, reusing the already allocated buffer space. See Also `java.io.ByteArrayInputStream#count`

public synchronized void reset()

Resets the count field of this ByteArrayOutputStream to zero, so that all currently accumulated output in the output stream is discarded. The output stream can be used again, reusing the already allocated buffer space.

See Also: java.io.ByteArrayInputStream#count

size back to summary

size	back to summary
public synchronized int size() Returns the current size of the buffer. Returns:int the value of the `count` field, which is the number of valid bytes in this output stream. See Also `java.io.ByteArrayOutputStream#count`

public synchronized int size()

Returns the current size of the buffer.

Returns:int: the value of the count field, which is the number of valid bytes in this output stream.
See Also: java.io.ByteArrayOutputStream#count

toByteArray back to summary

toByteArray	back to summary
public synchronized byte[] toByteArray() Creates a newly allocated byte array. Its size is the current size of this output stream and the valid contents of the buffer have been copied into it. Returns:byte[] the current contents of this output stream, as a byte array. See Also `java.io.ByteArrayOutputStream#size()`

public synchronized byte[] toByteArray()

Creates a newly allocated byte array. Its size is the current size of this output stream and the valid contents of the buffer have been copied into it.

Returns:byte[]: the current contents of this output stream, as a byte array.
See Also: java.io.ByteArrayOutputStream#size()

toString back to summary

toString	back to summary
public synchronized String toString() Overrides java.lang.Object.toString. Converts the buffer's contents into a string decoding bytes using the default charset. The length of the new `String` is a function of the charset, and hence may not be equal to the size of the buffer. This method always replaces malformed-input and unmappable-character sequences with the default replacement string for the default charset. The java.nio.charset.CharsetDecoder class should be used when more control over the decoding process is required. Returns:String String decoded from the buffer's contents. Annotations @Override Since 1.1 See Also `Charset#defaultCharset()`

public synchronized String toString()

Overrides java.lang.Object.toString.

Converts the buffer's contents into a string decoding bytes using the default charset. The length of the new String is a function of the charset, and hence may not be equal to the size of the buffer.

This method always replaces malformed-input and unmappable-character sequences with the default replacement string for the default charset. The java.nio.charset.CharsetDecoder class should be used when more control over the decoding process is required.

Returns:String

String decoded from the buffer's contents.

Annotations

@Override

Since

1.1

See Also

Charset#defaultCharset()

toString back to summary

toString	back to summary
public synchronized String toString(String charsetName) throws UnsupportedEncodingException Converts the buffer's contents into a string by decoding the bytes using the named `charset`. This method is equivalent to `#toString(charset)` that takes a `charset`. An invocation of this method of the form `ByteArrayOutputStream b; b.toString("UTF-8")` ByteArrayOutputStream b; b.toString("UTF-8") behaves in exactly the same way as the expression `ByteArrayOutputStream b; b.toString(StandardCharsets.UTF_8)` ByteArrayOutputStream b; b.toString(StandardCharsets.UTF_8) Parameters charsetName:String the name of a supported `charset` Returns:String String decoded from the buffer's contents. Exceptions UnsupportedEncodingException: If the named charset is not supported Since 1.1

public synchronized String toString(String charsetName) throws UnsupportedEncodingException

Converts the buffer's contents into a string by decoding the bytes using the named charset.

This method is equivalent to #toString(charset) that takes a charset.

An invocation of this method of the form

ByteArrayOutputStream b;
b.toString("UTF-8")

behaves in exactly the same way as the expression

ByteArrayOutputStream b;
b.toString(StandardCharsets.UTF_8)

Parameters

charsetName:String: the name of a supported charset

Returns:String

String decoded from the buffer's contents.

Exceptions

UnsupportedEncodingException:: If the named charset is not supported

Since

1.1

toString back to summary

toString	back to summary
public synchronized String toString(Charset charset) Converts the buffer's contents into a string by decoding the bytes using the specified `charset`. The length of the new `String` is a function of the charset, and hence may not be equal to the length of the byte array. This method always replaces malformed-input and unmappable-character sequences with the charset's default replacement string. The `java.nio.charset.CharsetDecoder` class should be used when more control over the decoding process is required. Parameters charset:Charset the charset to be used to decode the `bytes` Returns:String String decoded from the buffer's contents. Since 10

public synchronized String toString(Charset charset)

Converts the buffer's contents into a string by decoding the bytes using the specified charset. The length of the new String is a function of the charset, and hence may not be equal to the length of the byte array.

This method always replaces malformed-input and unmappable-character sequences with the charset's default replacement string. The java.nio.charset.CharsetDecoder class should be used when more control over the decoding process is required.

Parameters

charset:Charset: the charset to be used to decode the bytes

Returns:String

String decoded from the buffer's contents.

Since

toString back to summary

toString	back to summary
public synchronized String toString(int hibyte) Deprecated This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the `toString(String charsetName)` or `toString(Charset charset)` method, which takes an encoding-name or charset argument, or the `toString()` method, which uses the default charset. Creates a newly allocated string. Its size is the current size of the output stream and the valid contents of the buffer have been copied into it. Each character c in the resulting string is constructed from the corresponding element b in the byte array such that: `c == (char)(((hibyte & 0xff) << 8) \| (b & 0xff))` c == (char)(((hibyte & 0xff) << 8) \| (b & 0xff)) Parameters hibyte:int the high byte of each resulting Unicode character. Returns:String the current contents of the output stream, as a string. Annotations @Deprecated See Also `java.io.ByteArrayOutputStream#size()`, `java.io.ByteArrayOutputStream#toString(String)`, `java.io.ByteArrayOutputStream#toString()`, `Charset#defaultCharset()`

public synchronized String toString(int hibyte)

Deprecated

This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the toString(String charsetName) or toString(Charset charset) method, which takes an encoding-name or charset argument, or the toString() method, which uses the default charset.

Creates a newly allocated string. Its size is the current size of the output stream and the valid contents of the buffer have been copied into it. Each character c in the resulting string is constructed from the corresponding element b in the byte array such that:

c == (char)(((hibyte & 0xff) << 8) | (b & 0xff))

Parameters

hibyte:int: the high byte of each resulting Unicode character.

Returns:String

the current contents of the output stream, as a string.

Annotations

@Deprecated

write back to summary

write	back to summary
public synchronized void write(int b) Implements abstract java.io.OutputStream.write. Writes the specified byte to this `ByteArrayOutputStream`. Parameters b:int the byte to be written. Annotations @Override

public synchronized void write(int b)

Implements abstract java.io.OutputStream.write.

Writes the specified byte to this ByteArrayOutputStream.

Parameters

b:int: the byte to be written.

Annotations

@Override

write back to summary

write	back to summary
public synchronized void write(byte[] b, int off, int len) Overrides java.io.OutputStream.write. Writes `len` bytes from the specified byte array starting at offset `off` to this `ByteArrayOutputStream`. Annotations @Override Exceptions NullPointerException: if `b` is `null`. IndexOutOfBoundsException: if `off` is negative, `len` is negative, or `len` is greater than `b.length - off`

public synchronized void write(byte[] b, int off, int len)

Overrides java.io.OutputStream.write.

Writes len bytes from the specified byte array starting at offset off to this ByteArrayOutputStream.

Annotations

@Override

Exceptions

NullPointerException:: if b is null.
IndexOutOfBoundsException:: if off is negative, len is negative, or len is greater than b.length - off

writeBytes back to summary

writeBytes	back to summary
public void writeBytes(byte[] b) Writes the complete contents of the specified byte array to this `ByteArrayOutputStream`. API Note This method is equivalent to `write(b, 0, b.length)`. Parameters b:byte[] the data. Exceptions NullPointerException: if `b` is `null`. Since 11

public void writeBytes(byte[] b)

Writes the complete contents of the specified byte array to this ByteArrayOutputStream.

API Note

This method is equivalent to write(b, 0, b.length).

Parameters

b:byte[]: the data.

Exceptions

NullPointerException:: if b is null.

Since

writeTo back to summary

writeTo	back to summary
public synchronized void writeTo(OutputStream out) throws IOException Writes the complete contents of this `ByteArrayOutputStream` to the specified output stream argument, as if by calling the output stream's write method using `out.write(buf, 0, count)`. Parameters out:OutputStream the output stream to which to write the data. Exceptions IOException: if an I/O error occurs. NullPointerException: if `out` is `null`.

public synchronized void writeTo(OutputStream out) throws IOException

Writes the complete contents of this ByteArrayOutputStream to the specified output stream argument, as if by calling the output stream's write method using out.write(buf, 0, count).

Parameters

out:OutputStream: the output stream to which to write the data.

Exceptions

IOException:: if an I/O error occurs.
NullPointerException:: if out is null.

public Class ByteArrayOutputStream

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