Search code examples
javahashmaptreemap

Java putting Hashmap into Treemap

I am currently reading 2 million lines from a textfile as asked in the previous question Java Fastest way to read through text file with 2 million lines

Now I store these information into HashMap and I want to sort it via TreeMap because I want to use ceilingkey. Is the following method correct?

private HashMap<Integer, String> hMap = new HashMap();

private TreeMap<Integer, String> tMap = new TreeMap<Integer, String>(hMap);
Solution 
  • HashMap<Integer, String> hashMap = new HashMap<Integer, String>();
TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>();
treeMap.putAll(hashMap);

    Should work anyway.