May 7, 2015 · Map map = new HashMap(); Hashtable ht = new Hashtable(); Both classes can be found from the java.util package. The difference between the 2 is explained in the following jGuru FAQ entry .

HashTable and HashMap are member of the Java Collections Framework (since Java 2 platform v1.2, HashTable was retrofitted to implement the Map interface). HashTable is considered legacy code, the documentation advise to use ConcurrentHashMap in place of Hashtable if a thread-safe highly-concurrent implementation is desired.

Mar 8, 2012 · In C# you can initialize Hashtables (and many other types of objects) using code like this - Hashtable table = new Hashtable {{1, 1}, {2, 2}}; Is there anything like this in Java or do you have to...

Apr 11, 2016 · Using for loop to get key by value is not time effecient!! and you don't benefit from HashTable. So since you want to use hashtable for straight and reverse retrival you may use two hashtables. Table1 (key, value) Table2 (value, key)

Nov 26, 2013 · I'm working on an Android project in which I have to get all the values from a hash table regardless the key. My map is HashMap<String, ArrayList<MyProduct>> orderAdap =

Feb 28, 2010 · You need to use an explicit java.util.Iterator to iterate over the Map's entry set rather than being able to use the enhanced For-loop syntax available in Java 6. The following example iterates over a Map of Integer , String pairs, removing any entry whose Integer key …

Nov 22, 2011 · A better replacement for Hashtable is HashMap. As for being obsolete, I have no reference to it, but the Javadoc states: As of the Java 2 platform v1.2, this class was retrofitted to implement the Map interface, making it a member of the Java Collections Framework. Hashtable is synchronized unlike HashMap.

Sep 26, 2008 · A hashtable, on the other hand, has an associated function that takes an entry, and reduces it to a number, a hash-key. This number is then used as an index into the array, and this is where you store the entry. A hashtable revolves around an …

Dec 2, 2010 · Hashtable is a legacy collection which was replaced by Java 1.2 collections in 1998. I suggest you avoid it, along with Vector and Enumeration. Instead of Hashtable use HashMap where possible. You can add synchronization using Collections.synchronizedMap(map) if you need it. Instead of Vector, use ArrayList where possible.

Sep 3, 2014 · Java doc says this about Scanner.hasnext. public boolean hasNext() Returns true if this scanner has another token in its input.