Java

Types

type note
byte 8-bit signed two's complement integer
short 16-bit signed two's complement integer
int 32-bit signed two's complement integer
long 64-bit two's complement integer
float single-precision 32-bit IEEE 754 floating point
double double-precision 64-bit IEEE 754 floating point
boolean the size isn't precisely defined

Numeric literals

You can use underscore characters in SE7+
example: long hexBytes = 0xFF_CC_DA_B5;


AES intrinsics


Requires Java 8 and Intel 2010+ Westmere

-XX:+UseAES -XX:+UseAESIntrinsics

Zero copy

Avoid copying the file data across user/kernel boundary, instead have the kernel put the file in a buffer and use DMA to pass the data directly.

https://www.ibm.com/developerworks/linux/library/j-zerocopy/