Here is a simple example on how to convert HashMap to ArrayList in Java.
Java Example:
package com.crunchify;
/**
* @author Crunchify.com
*/
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
public class CrunchifyHashmapToArrayList {
public static void main(String... args) {
HashMap<String, Integer> companyDetails = new HashMap<String, Integer>();
// create hashmap with keys and values (CompanyName, #Employees)
companyDetails.put("eBay", 4444);
companyDetails.put("Paypal", 5555);
companyDetails.put("IBM", 6666);
companyDetails.put("Google", 7777);
companyDetails.put("Yahoo", 8888);
System.out.println("==> Size of companyDetails Map: " + companyDetails.size());
Iterator it = companyDetails.entrySet().iterator();
while (it.hasNext()) {
Map.Entry pairs = (Map.Entry) it.next();
System.out.println(pairs.getKey() + " = " + pairs.getValue());
}
// Converting HashMap keys into ArrayList
List<String> keyList = new ArrayList<String>(companyDetails.keySet());
System.out.println("\n==> Size of Key list: " + keyList.size());
for (String temp : keyList) {
System.out.println(temp);
}
// Converting HashMap Values into ArrayList
List<Integer> valueList = new ArrayList<Integer>(companyDetails.values());
System.out.println("\n==> Size of Value list: " + valueList.size());
for (Integer temp : valueList) {
System.out.println(temp);
}
List<Entry> entryList = new ArrayList<Entry>(companyDetails.entrySet());
System.out.println("\n==> Size of Entry list: " + entryList.size());
for (Entry temp : entryList) {
System.out.println(temp);
}
}
}
Output:
==> Size of companyDetails Map: 5 IBM = 6666 Yahoo = 8888 Google = 7777 Paypal = 5555 eBay = 4444 ==> Size of Key list: 5 IBM Yahoo Google Paypal eBay ==> Size of Value list: 5 6666 8888 7777 5555 4444 ==> Size of Entry list: 5 IBM=6666 Yahoo=8888 Google=7777 Paypal=5555 eBay=4444