THE PACKAGE JAVA.IO

java.io.InputStream

22.3

stream is at end of file, the value

 1

 is returned; otherwise, at least one byte is read

and stored into

b

.

The first byte read is stored into element

b[0]

, the next one into

b[1]

, and so

on. The number of bytes read is, at most, equal to the length of

b

. Let

k

 be the

number of bytes actually read; these bytes will be stored in elements

b[0]

 through

b[

k

 1]

, leaving elements

b[

k

]

 through

b[b.length 1]

 unaffected.

If the first byte cannot be read for any reason other than end of file, then an

IOException

 is thrown. In particular, an

IOException

 is thrown if the input

stream has been closed ( 22.15.5).

The

read(b)

 method for class

InputStream

 has the same effect as:

read(b, 0, b.length)

22.3.3

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

throws IOException, NullPointerException,

IndexOutOfBoundsException

The general contract of

read(b, off, len)

 is that it reads some number of

bytes from the input stream and stores them into the buffer array

b

. An attempt is

made to read as many as

len

 bytes, but a smaller number may be read, possibly

zero. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an

exception is thrown.

If

b

 is

null

, a

NullPointerException

 is thrown.

If

off

 is negative, or

len

 is negative, or

off+len

 is greater than the length of

the array

b

, then an

IndexOutOfBoundsException

 is thrown.

If

len

 is zero, then no bytes are read and

0

 is returned; otherwise, there is an

attempt to read at least one byte. If no byte is available because the stream is at

end of file, the value

 1

 is returned; otherwise, at least one byte is read and stored

into

b

.

The first byte read is stored into element

b[off]

, the next one into

b[off+1]

,

and so on. The number of bytes read is, at most, equal to

len

. Let

k

 be the number

of bytes actually read; these bytes will be stored in elements

b[off]

 through

b[off+

k

 1]

, leaving elements

b[off+

k

]

 through

b[off+len 1]

 unaffected.

In every case, elements

b[0]

 through

b[off]

 and elements

b[off+len]

through

b[b.length 1]

 are unaffected.

If the first byte cannot be read for any reason other than end of file, then an

IOException

 is thrown. In particular, an

IOException

 is thrown if the input

stream has been closed ( 22.15.5).

The

read(b, off, len)

 method for class

InputStream

 simple calls the

method

read()

 repeatedly. If the first such call results in an

IOException

, that

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