List<String> list = new ArrayList<String>;

public void myMethod(){
        Iterator<String> it = list.iterator();
        while (it.hasNext()) {
        if (stringMethod(it.next())) {
            it.remove();
        }
    }
}

public boolean stringMethod(String s) {
        final boolean shouldRemove = shouldRemove(s);
    if (condition) {
        for (String s1 : list) { //concurrentmodificationexception on this line
            if (shouldRemove && s1 == s) {
                continue;
            }
            //do stuff
        }
    }
        return shouldRemove;
}

private boolean shouldRemove(String s) {
    // do stuff
}