Is it possible to read/write bits from a file using JAVA?

Question

To read/write binary files, I am using DataInputStream/DataOutputStream, they have this method writeByte()/readByte(), but what I want to do is read/write bits? Is it possib

Answer 1

It's not possible to read/write individual bits directly, the smallest unit you can read/write is a byte.

You can use the standard bitwise operators to manipulate a byte though, so e.g. to get the lowest 2 bits of a byte, you'd do

byte b = in.readByte();
byte lowBits = b&0x3;

set the low 4 bits to 1, and write the byte:

b |= 0xf;
out.writeByte(b);

(Note, for the sake of efficiency you might want to read/write byte arrays and not single bytes)