Java : ByteArrayInputStream with Examples

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10
System.out.println(is.read()); // 20

System.out.println(Arrays.toString(is.readAllBytes())); // [30, 40, 50]

protected byte[] buf

An array of bytes that was provided by the creator of the stream.

protected. I think it's rare to create a subclass of this class. Therefore, the code example is omitted.

protected int count

The index one greater than the last valid byte in the input stream buffer.

protected. I think it's rare to create a subclass of this class. Therefore, the code example is omitted.

protected int mark

The currently marked position in the stream.

protected. I think it's rare to create a subclass of this class. Therefore, the code example is omitted.

protected int pos

The index of the next byte to read from the input stream buffer.

protected. I think it's rare to create a subclass of this class. Therefore, the code example is omitted.

ByteArrayInputStream (byte[] buf)

Creates a ByteArrayInputStream so that it uses buf as its buffer array.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10
System.out.println(is.read()); // 20

System.out.println(Arrays.toString(is.readAllBytes())); // [30, 40, 50]

ByteArrayInputStream (byte[] buf, int offset, int length)

Creates ByteArrayInputStream that uses buf as its buffer array.

final byte[] buf = {10, 20, 30, 40};

final var is1 = new ByteArrayInputStream(buf, 0, 0);
System.out.println(Arrays.toString(is1.readAllBytes())); // []

final var is2 = new ByteArrayInputStream(buf, 0, 1);
System.out.println(Arrays.toString(is2.readAllBytes())); // [10]

final var is3 = new ByteArrayInputStream(buf, 0, 2);
System.out.println(Arrays.toString(is3.readAllBytes())); // [10, 20]

final var is4 = new ByteArrayInputStream(buf, 0, 3);
System.out.println(Arrays.toString(is4.readAllBytes())); // [10, 20, 30]

final var is5 = new ByteArrayInputStream(buf, 0, 4);
System.out.println(Arrays.toString(is5.readAllBytes())); // [10, 20, 30, 40]

final var is6 = new ByteArrayInputStream(buf, 0, 5);
System.out.println(Arrays.toString(is6.readAllBytes())); // [10, 20, 30, 40]

final byte[] buf = {10, 20, 30, 40};

final var is1 = new ByteArrayInputStream(buf, 0, 4);
System.out.println(Arrays.toString(is1.readAllBytes())); // [10, 20, 30, 40]

final var is2 = new ByteArrayInputStream(buf, 1, 3);
System.out.println(Arrays.toString(is2.readAllBytes())); // [20, 30, 40]

final var is3 = new ByteArrayInputStream(buf, 2, 2);
System.out.println(Arrays.toString(is3.readAllBytes())); // [30, 40]

final var is4 = new ByteArrayInputStream(buf, 3, 1);
System.out.println(Arrays.toString(is4.readAllBytes())); // [40]

final var is5 = new ByteArrayInputStream(buf, 4, 0);
System.out.println(Arrays.toString(is5.readAllBytes())); // []

int available ()

Returns the number of remaining bytes that can be read (or skipped over) from this input stream.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.available()); // 5
System.out.println(is.read()); // 10

System.out.println(is.available()); // 4
System.out.println(is.read()); // 20

System.out.println(is.available()); // 3
System.out.println(is.read()); // 30

System.out.println(is.available()); // 2
System.out.println(is.read()); // 40

System.out.println(is.available()); // 1
System.out.println(is.read()); // 50

System.out.println(is.available()); // 0
System.out.println(is.read()); // -1

void close ()

Closing a ByteArrayInputStream has no effect.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

// Closing a stream has no effect.
is.close();

// The methods in this class can be called after the stream has been closed.
System.out.println(Arrays.toString(is.readAllBytes())); // [10, 20, 30, 40, 50]

void mark (int readAheadLimit)

Set the current marked position in the stream.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10
System.out.println(is.read()); // 20
System.out.println(is.read()); // 30

// Note: The readAheadLimit for this class has no meaning.
is.mark(0);

System.out.println(is.read()); // 40
System.out.println(is.read()); // 50
System.out.println(is.read()); // -1

is.reset();

System.out.println(is.read()); // 40
System.out.println(is.read()); // 50
System.out.println(is.read()); // -1

boolean markSupported ()

Tests if this InputStream supports mark/reset.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);
System.out.println(is.markSupported()); // true

int read ()

Reads the next byte of data from this input stream.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10
System.out.println(is.read()); // 20
System.out.println(is.read()); // 30
System.out.println(is.read()); // 40
System.out.println(is.read()); // 50
System.out.println(is.read()); // -1

int read (byte[] b, int off, int len)

Reads up to len bytes of data into an array of bytes from this input stream.

final byte[] buf = {10, 20, 30, 40, 50};
final byte[] b = new byte[10];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

System.out.println(is.read(b, 0, 10)); // 5
System.out.println(Arrays.toString(b)); // [10, 20, 30, 40, 50, 0, 0, 0, 0, 0]

final byte[] buf = {10, 20, 30, 40, 50, 60, 70};
final byte[] b = new byte[5];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 0]

System.out.println(is.read(b, 0, 1)); // 1
System.out.println(Arrays.toString(b)); // [10, 0, 0, 0, 0]

System.out.println(is.read(b, 0, 2)); // 2
System.out.println(Arrays.toString(b)); // [20, 30, 0, 0, 0]

System.out.println(is.read(b, 0, 3)); // 3
System.out.println(Arrays.toString(b)); // [40, 50, 60, 0, 0]

System.out.println(is.read(b, 0, 4)); // 1
System.out.println(Arrays.toString(b)); // [70, 50, 60, 0, 0]

System.out.println(is.read(b, 0, 5)); // -1
System.out.println(Arrays.toString(b)); // [70, 50, 60, 0, 0]

final byte[] buf = {10, 20, 30, 40, 50};
final byte[] b = new byte[5];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 0]

System.out.println(is.read(b, 4, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 10]

System.out.println(is.read(b, 3, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 0, 0, 20, 10]

System.out.println(is.read(b, 2, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 0, 30, 20, 10]

System.out.println(is.read(b, 1, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 40, 30, 20, 10]

System.out.println(is.read(b, 0, 1)); // 1
System.out.println(Arrays.toString(b)); // [50, 40, 30, 20, 10]

final byte[] buf = {10, 20, 30, 40, 50, 60, 70};
final byte[] b = new byte[3];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0]

System.out.println(is.read(b, 0, 3)); // 3
System.out.println(Arrays.toString(b)); // [10, 20, 30]

//is.read(b, 0, 4); // IndexOutOfBoundsException
//is.read(b, 3, 1); // IndexOutOfBoundsException

byte[] readAllBytes ()

Reads all remaining bytes from the input stream.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

final var ret = is.readAllBytes();
System.out.println(Arrays.toString(ret)); // [10, 20, 30, 40, 50]

int readNBytes (byte[] b, int off, int len)

Reads the requested number of bytes from the input stream into the given byte array.

final byte[] buf = {10, 20, 30, 40, 50};
final byte[] b = new byte[10];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

System.out.println(is.readNBytes(b, 0, 10)); // 5
System.out.println(Arrays.toString(b)); // [10, 20, 30, 40, 50, 0, 0, 0, 0, 0]

final byte[] buf = {10, 20, 30, 40, 50, 60, 70};
final byte[] b = new byte[5];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 0]

System.out.println(is.readNBytes(b, 0, 1)); // 1
System.out.println(Arrays.toString(b)); // [10, 0, 0, 0, 0]

System.out.println(is.readNBytes(b, 0, 2)); // 2
System.out.println(Arrays.toString(b)); // [20, 30, 0, 0, 0]

System.out.println(is.readNBytes(b, 0, 3)); // 3
System.out.println(Arrays.toString(b)); // [40, 50, 60, 0, 0]

System.out.println(is.readNBytes(b, 0, 4)); // 1
System.out.println(Arrays.toString(b)); // [70, 50, 60, 0, 0]

System.out.println(is.readNBytes(b, 0, 5)); // 0
System.out.println(Arrays.toString(b)); // [70, 50, 60, 0, 0]

final byte[] buf = {10, 20, 30, 40, 50};
final byte[] b = new byte[5];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 0]

System.out.println(is.readNBytes(b, 4, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 0, 0, 0, 10]

System.out.println(is.readNBytes(b, 3, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 0, 0, 20, 10]

System.out.println(is.readNBytes(b, 2, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 0, 30, 20, 10]

System.out.println(is.readNBytes(b, 1, 1)); // 1
System.out.println(Arrays.toString(b)); // [0, 40, 30, 20, 10]

System.out.println(is.readNBytes(b, 0, 1)); // 1
System.out.println(Arrays.toString(b)); // [50, 40, 30, 20, 10]

final byte[] buf = {10, 20, 30, 40, 50, 60, 70};
final byte[] b = new byte[3];

final var is = new ByteArrayInputStream(buf);

System.out.println(Arrays.toString(b)); // [0, 0, 0]

System.out.println(is.readNBytes(b, 0, 3)); // 3
System.out.println(Arrays.toString(b)); // [10, 20, 30]

//is.readNBytes(b, 0, 4); // IndexOutOfBoundsException
//is.readNBytes(b, 3, 1); // IndexOutOfBoundsException

void reset ()

Resets the buffer to the marked position.

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10
System.out.println(is.read()); // 20
System.out.println(is.read()); // 30

// Note: The readAheadLimit for this class has no meaning.
is.mark(0);

System.out.println(is.read()); // 40
System.out.println(is.read()); // 50
System.out.println(is.read()); // -1

is.reset();

System.out.println(is.read()); // 40
System.out.println(is.read()); // 50
System.out.println(is.read()); // -1

long skip (long n)

Skips n bytes of input from this input stream.

final byte[] buf = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10

System.out.println(is.skip(1)); // 1
System.out.println(is.read()); // 30

System.out.println(is.skip(2)); // 2
System.out.println(is.read()); // 60

System.out.println(is.skip(3)); // 3
System.out.println(is.read()); // 100

System.out.println(is.skip(1)); // 0
System.out.println(is.read()); // -1

final byte[] buf = {10, 20, 30, 40, 50};

final var is = new ByteArrayInputStream(buf);

System.out.println(is.read()); // 10

System.out.println(is.skip(10)); // 4
System.out.println(is.read()); // -1

System.out.println(is.skip(1)); // 0
System.out.println(is.read()); // -1

nullInputStream, read, readNBytes, skipNBytes, transferTo

Please see the link below.

• InputStream with Examples