Validation Loop That Runs Until User Enters A Valid Binary

I'm trying to do a user validation loop that runs until the user enters a valid binary, q, or Q. I think the rest of my program should work as intended, but here is the areas of concern:

public static boolean isBinary(String num) //Check if the entry is binary
{
for(int i = 0; i < num.length(); i++) {
if(num.charAt(i) != 0 || num.charAt(i) != 1){
return false;

[Code] .....

The program runs without errors otherwise.