Alas, the front has been skipped, a look at the pure text description on the headache.
This section is about Java data types, there are eight basic types, of which the int,short,long,byte four are shaped, is pure numbers, the size is 4,2,8,1 bytes, a byte is composed of 8 01, the highest bit is the sign bit, 0 is an integer, 1 is a negative number, For example, the range of byte is 128 to 127. I don't know the rest of it.
Floating-point types have float single-precision and double double-precision, which are 4 bytes and 8 bytes, respectively.
The char type represents a single character, accounting for two bytes, and its value corresponds to the Unicode-encoded value. For example, judging a string which has Chinese characters, you can turn the string into char type, find the range of Unicode encoding of Chinese characters on the Internet, and determine whether the value of char is in this range to know if it is a Chinese character.
The last Boolean type is the simplest, with only two values, true and false.
At this point eight basic types are finished, relatively simple.
Java Learning Path Java Core Technology 3.3