- while program running, may have dif vals @ dif times
- constant: lock assigned vals so that no changes can take place
  - declaration: final <type> <NAME> = <value>;
  - Java naming convention: only capital letters and underscores
  - judicious use increases readability
- named constant: referred to w/ identifier
- literal constant: referred to w/ actual value
- integer const data type default int
  - specify long by appending l or L
- real const data type default double
  - specify float by appending f or F
  - specify double
    - optional
    - d or D
- scientific notation
  - number * 10^exponent
  - exponential notation syntax: <number> E <exponent>
  - <number>
    - literal const
    - may contain decimal point
  - can use e instead of E
  - <exponent>
    - signed or unsigned int
  - may suffix entire expression w/ float and double modifiers