| Name | Range | Storage Size |
|---|---|---|
| byte | -27 to 27 - 1 (-128 to 127) | 8-bit signed |
| short | -215 to 215 - 1 (-32768 to 32767) | 16-bit signed |
| int | -231 to 231 - 1 (-2147483648 to 2147483647) | 32-bit signed |
| long | -263 to 263 - 1 (i.e., -9223372036854775808 to 9223372036854775807) | 64-bit signed |
| float | Negative range: -3.4028235E + 38 to -1.4E - 45 Positive range: 1.4E - 45 to 3.4028235E + 38 | 32-bit IEEE 754 |
| double | Negative range: -1.7976931348623157E + 308 to -4.9E - 324 Positive range: 4.9E - 324 to 1.7976931348623157E + 308 | 64-bit IEEE 754 |
不是27或者 -27，上下标不正确，找不到markdown数学公式说明，再修改。
总之，Java 数字数据类型有6种，byte是和 C++ 相比多出来的一种，是一种数字类型，比较像 signed char，因为范围是一样的， -128 ~ 127。
[1] Introduction to Java Programming 10th chapter 2.9