Java
| Label |
Size |
Range |
| Java Byte |
1 byte |
-128 to 127 |
| Java Short |
2 byte |
-3.2 * 10^4 to 3.2 * 10^4 |
| Java Int |
4 byte |
-2 * 10^9 to 2 * 10^9 |
| Java Long |
8 byte |
-9 * 10^18 to 9 * 10^18 |
| Java Float |
4 byte |
Sufficient for storing 6 to 7 decimal digits |
| Java Double |
8 byte |
Sufficient for storing 15 decimal digits |
| Java Boolean |
1 bit |
|
| Java Char |
2 bytes |
|
# Widening Casting (automatically) - converting a smaller type to a larger type size
byte -> short -> char -> int -> long -> float -> double
# Narrowing Casting (manually) - converting a larger type to a smaller size type
double -> float -> long -> int -> char -> short -> byte
Latency
L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns
Compress 1K bytes with Zippy ............. 3,000 ns = 3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs
SSD random read ........................ 150,000 ns = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs
Round trip within same datacenter ...... 500,000 ns = 0.5 ms
Read 1 MB sequentially from SSD* ..... 1,000,000 ns = 1 ms
Disk seek ........................... 10,000,000 ns = 10 ms
Read 1 MB sequentially from disk .... 20,000,000 ns = 20 ms
Send packet CA->Netherlands->CA .... 150,000,000 ns = 150 ms