Bits, Bytes, Characters.

bit is smallest unit of information, either 0 or 1.

byte is unit of 8 bits, or in more advanced, more modern or future machines it's 16, 32, 64, 128, ...

central processing unit's (processor's) architecture makes it natural to use larger bytes, code is more optimal that way.

more of memory can be used in computer as well, because of adressing memory with more-bit numbers.

8-bit byte allows for storing (representing) in memory 2⁸ = 256 different numbers or other symbols.

8-bit byte allows for storing in memory ASCII-encoded character (letter for example).



ASCII-encoded character table, part of ...

there are also other forms of encoding letters & other characters, proper Unicode for example.

since version 5.2. unicode allows for encoding Vedic Sanskrit characters as well.

Java uses Unicode-encoded characters.

Unicode standard has many substandards, that use different amount of bits for encoding a character.

for example: UTF-1, UTF-7, UTF-8, UTF-EBCDIC, UTF-16, UTF-32.

occasionally two bytes are called: 'word', perhaps there's more of that ...