2. [Mandatory] ‘L’ instead of ‘l’ should be used for long or Long variable because ‘l’ is easily to be regarded as number 1 in mistake.

3. [Recommended] Constants should be placed in different constant classes based on their functions. For example, cache related constants could be put in CacheConsts while configuration related constants could be kept in ConfigConsts.

5. [Recommended] Use an enumeration class if values lie in a fixed range or if the variable has attributes. The following example shows that extra information (which day it is) can be included in enumeration: