Date: 2013jun20
Update: 2025oct2
Language: Java
Keywords: LinkedHashSet, insert
Q. Java: A HashMap randomizes the order of keys. How can I keep keys in add order?
A. Use LinkedHashMap.
The entrySet() will be in the same order as they keys were added.
(Not necessarily alphabetical order)
I used this class when I wanted to read the section of a .ini file
in. And then write it out with a small change but not radically
changing the order of the keys. Full example:
import java.util.LinkedHashMap;
class Demo {
public static final void main(String[] args) {
LinkedHashMap<String,String> map = new LinkedHashMap<String,String>();
map.put("One", "1");
map.put("Two", "2");
map.put("Three", "3");
for (String key : map.keySet()) {
System.out.println("key=" + key);
}
}
}
Output:
key=One
key=Two
key=Three