convert Object[] from a hashmap keyset to String[]?
hashmap, java
Solution
You can't simply cast an `Object[]` array to a `String[]` array. You should instead use the generic version of `toArray`, which should work better:
String[] keyArray = keys.toArray(new String[keys.size()]);
Also note that you could simply iterate over the `entrySet` (that will save all the `get` calls) and use a StringBuilder for better string concatenation efficiency:
StringBuilder hashmapDetails = new StringBuilder();
for(Map.Entry<String, String> e : mappings.entrySet()) {
String[] details = e.getKey().split("/");
hashmapDetails += details[1];
hashmapDetails += e.getValue();
hashmapDetails += ";";
}
String result = hashmapDetails.substring(0, hashmapDetails.length() - 1);
Problem
``` Set<String> keys = mappings.keySet(); String[] keyArray = (String[]) keys.toArray(); String hashmapDetails = ""; for(int p=0; p < keyArray.length; p++){ String[] details = keyArray[p].split("/"); hashmapDetails += details[1]; hashmapDetails += mappings.get(keyArray[p]); if (p != keyArray.length -1){ hashmapDetails += ";"; } } ``` Pardon my lack of understanding but I'm trying to explore the usage of hashmaps. I understand that the toArray() returns an Object[]. However, is it not possible to type cast it to a String[]? As you can see in the codes, later, I need to go through an array and do some splitting and other String manipulation. By doing this I got an error: ``` java.lang.ClassCastException: java.lang.Object[] cannot be cast to java.lang.String[] ``` Any guidance on how I should tackle this is greatly appreciated. Thanks!