iterating through Enumeration of hastable keys throws NoSuchElementException error

Question

I am trying to iterate through a list of keys from a hash table using enumeration however I keep getting a NoSuchElementException at the last key in list?

Hasht         


        

Answer 1

You're calling nextElement twice in the loop. You should call it only once, else it moves ahead twice:

while(e.hasMoreElements()){
    String s = e.nextElement();
    System.out.println(s);
}

Answer 2

You're calling e.nextElement() twice inside your loop when you're only guaranteed that you can call it once without an exception. Rewrite the loop like so:

while(e.hasMoreElements()){
  String param = e.nextElement();
  System.out.println(param);
}

Answer 3

for (String key : Collections.list(e))
    System.out.println(key);

Answer 4

Every time you call e.nextElement() you take the next object from the iterator. You have to check e.hasMoreElement() between each call.

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Example:

while(e.hasMoreElements()){
    String param = e.nextElement();
    System.out.println(param);
}

Answer 5

You call nextElement() twice in your loop. This call moves the enumeration pointer forward. You should modify your code like the following:

while (e.hasMoreElements()) {
    String param = e.nextElement();
    System.out.println(param);
}

Answer 6

You are calling nextElement twice. Refactor like this:

while(e.hasMoreElements()){


String param = (String) e.nextElement();
System.out.println(param);
}