No Repeats
Write a Java program contained in a single file named "" that uses a
loop to have the user enter a list of up to ten words (or phrases), one per line.
The user should signal the end of the list by pressing the ENTER key by itself on
an empty line.  Your program must require the user to enter at least one word or
phrase (by continuously querying the user until at least one entry is made), and
it should not allow the user to enter more than ten words or phrases (after the
tenth entry it should stop asking for new input).  Your program must eliminate
leading and trailing spaces from all user input.

In addition to the above requirements, your program must use a loop to prevent
the user from entering duplicate words or phrases.  If the user enters a word
or phrase that has already been entered, discard that entry, tell the user
that duplicate entries are not allowed, and then have the user enter a new
word or phrase.  Your program should not modify the case of the words or
phrases, but it should ignore case when checking for duplicate entries.

Finally, after the user has entered up to ten unique words or phrases, your
program should use a loop to display the word/phrase list back to the user,
one entry per line.  The words/phrases should be displayed back to the user in
the same order in which they were entered.  When displaying the list, if it
contains fewer than ten words or phrases, make sure no blank (empty) lines or
'null' entries are displayed.

For this program you must use a built-in Java array of strings to store the
words and phrases.  You are allowed to use only one array, and you may not use
any other type of List (such as an ArrayList) or Collection anywhere in your
program.  Also, the maximum number of entries allowed (10) should be stored in
your program as a globally-defined integer constant (all capital letters), and
with the exception of the line where you define the constant, the number 10 (or
9 or 11) should not appear anywhere in your program.

Other than the global constant and array of strings, you may not use any global
variables for this assignment.  In addition to 'main', you should have a
separate method that gets the entries from the user, another method that checks
for duplicate entries, and another method that displays the word/phrase list
back to the user.

Advanced Option
When displaying the words back to the user, display the words arranged in
order by length (number of characters), with the shortest word shown first.
If the list contains multiple words with the same number of characters, then
that group of words should be displayed in ascending alphabetical order
(within the larger list of words, which should still be sorted by length).
You may use additional arrays for this advanced option.