Feb 7, 2013 · I'd like to create a map that contains entries consisting of (int, Point2D) How can I do this in Java? I tried the following unsuccessfully. HashMap hm = new HashMap(); hm.put(1, new …

Is there an object in Java that acts like a Map for storing and accessing key/value pairs, but can return an ordered list of keys and an ordered list of values, such that the key and value lists ar...

What is the best way to combine two lists into a map? It would be nice to use for (String item: list), but it will only iterate through one list, and you'd need an explicit iterator for the other l...

Feb 3, 2009 · How would you initialise a static Map in Java? Method one: static initialiser Method two: instance initialiser (anonymous subclass) or some other method? What are the pros and cons of …

Feb 7, 2017 · Is there a way to create a map with keys and values at the same time (I mean a one-line code)? For example, I create a map named map, and I need to use the method "put" whenever I …

Java 9 added a series of Map.of static methods to do just what you want: Instantiate an immutable Map using literal syntax. The map (a collection of entries) is immutable, so you cannot add or remove …

Jan 18, 2022 · java.lang.reflect.InaccessibleObjectException: Unable to make field private final java.util.Comparator java.util.TreeMap.comparator accessible:module [duplicate] Asked 3 years, 11 …

List differs from Map in the conceptual way -- Map have notion of 'key, value' pair, whereas List doesn't. Given this it's unclear how exactly you going to convert from List to Map and back.

My questions are: 1) In general, would overriding equals and hashcode of the key class of the map resolve this issue and the map can be correctly restored? 2) If my key is a String and the String class …

Jun 22, 2009 · How do I convert a Map<key,value> to a List<value>? Should I iterate over all map values and insert them into a list?