we will see about LinkedHashMap in java. LinkedHashMap is same as HashMap except that it maintains insertion order.
Some points about LinkedHashMap
- LinkedHashMap implements Map interface and extends HashMap class.
- LinkedHashMap maintains insertion order, so when you will be able to access elements in the order they were inserted like ArrayList.
- LinkedHashMap maintains doubly Linked list to maintain insertion order.
Example:
LinkedHashMapMain.java
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package org.arpit.java2blog;
import java.util.LinkedHashMap;
public class LinkedHashMapMain {
public static void main(String args[])
{
// LinkedHashMap with Country as key and capital as value
// LinkedHashMap maintains insertion order
LinkedHashMap<String,String> countryCapitalMap=new LinkedHashMap<String,String>();
countryCapitalMap.put("India","Delhi");
countryCapitalMap.put("Japan","Tokyo");
countryCapitalMap.put("France","Paris");
countryCapitalMap.put("Russia","Moscow");
System.out.println("-----------------------------");
// Iterating Using keySet() and for each loop
System.out.println("Iterating Using keySet() and for each loop");
for (String countryKey:countryCapitalMap.keySet()) {
System.out.println("Country:"+ countryKey +" and Capital:"+countryCapitalMap.get(countryKey));
}
System.out.println("-----------------------------");
}
}
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