Why is it bad practice to declare variables on one line?
e.g.
private String var1, var2, var3
instead of:
private
Relevance.
Just because two variables are of type String does not mean they are closely related to each other.
If the two (or more) variables are closely related by function, rather then variable type, then maybe they could be declared together. i.e. only if it makes sense for a reader of your program to see the two variables together should they actually be placed together