Which do you prefer and why"
String myString = null;
if(someCondition)
myString = "something";
else
myString = "something else";
OR
String myString = "";
if(someCondition)
myString = "something";
else
myString = "something else";
I know that using the ternary (? :) operator is possible but I'd like to know about the above two.
Neither. Instead, this:
String myString;
if (someCondition)
myString = "something";
else
myString = "something else";
In both of your alternatives, the variable is initialized with a value which will never ever be read. The fact that it's present at all is misleading.
I would actually use the conditional operator, of course - but barring that, the above is the better option.