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POUpdate HashMap values of type HashSet<Integer>
 

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    <p>I have trouble updating the HashMap values of Set type. After initializing the HashMap with key-values pair, I want to insert a new value to the the existing value Set, and the new value is to be incremented for each insert. My code is following:</p> <pre><code> public static void main(String[] args) { String[] mapKeys = new String[]{"hello", "world", "america"}; Map&lt;String, Set&lt;Integer&gt;&gt; hashMap1 = new HashMap&lt;String, Set&lt;Integer&gt;&gt;(); Set&lt;Integer&gt; values = new HashSet&lt;Integer&gt;(); for (int i = 0; i &lt; 10; i++) // initialize the values to a set of integers[1 through 9] { values.add(i); } for (String key : mapKeys) { hashMap1.put(key, values); } StdOut.println("hashMap1 is: " + hashMap1.toString()); int newValues = 100; // insert this newValues (incremented at each insert) to each value Set&lt;Integer&gt; valuesCopy; for (String key : mapKeys) { if (hashMap1.containsKey(key)) { valuesCopy = hashMap1.get(key); // first, copy out the existing values valuesCopy.add(newValues++); // insert the newValues to the value Set hashMap1.remove(key);// remove the existing entries hashMap1.put(key, valuesCopy); // insert the key-value pairs } } StdOut.println("the updated hashMap1 is: " + hashMap1.toString()); } </code></pre> <p>When executing the code, each HashMap key is associated with the same set of Integers: [102, 0, 1, 2, 100, 3, 101, 4, 5, 6, 7, 8, 9], however, what I really want is insert only one number to each set, this is what I want: [0, 1, 2, 100, 3, 4, 5, 6, 7, 8, 9]</p> <p>I need help understanding this: why all the new inserted values are the same? how to make it work as I wish? thanks for help</p>
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