if the expression or variable is null, it’s still work;

check the variable’s type and caller function belong to the varable;

if you are not understand the original code immediately, but you understand after your deep thinking, write comment about it;

incomming params check;

return value maybe default value or just null, especially return empty object.

if the expression or variable is null, it’s still work;

check the variable’s type and caller function belong to the varable;

if you are not understand the original code immediately, but you understand after your deep thinking, write comment about it;

incomming params check;

return value maybe default value or just null, especially return empty object.