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Convert HashMap Keys to String Array in Java

  By hitesh | February 5, 2013 | Java

I was working with HashMap and i wanted to convert all the keys inside the HashMap to array of String. So i tried casting the Object to String since Object is the class from where String is derived. But i got class cast exception. Started looking on what is the issue and found that you cannot directly cast the Object[] to String[]. You have to manually iterate through and create String[] array.

Assume you have an HashMap and you get all the keyset for that HashMap

1 2	Map<String, String> appNames = new HashMap<String, String>();     Object[] appArray = appNames.keySet().toArray();

Since the received array is of type Object, we would have to iterate through it to get the String array.

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public static String[] convertToString(Object[] objectArray){        String[] strArray = new String[objectArray.length];        for (int i = 0; i < objectArray.length; i++)        {            strArray[i] = new String((String) objectArray[i]);        }        return strArray;     }

Happy coding