Create Map in Java

Question

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 Point2D Double 50  50

User · Answer

Map lt Integer  Point2D gt  hm   new HashMap lt Integer  Point2D gt

User · Answer

I use such kind of a Map population thanks to Java 9  In my honest opinion  this approach provides more readability to the code     public static void main String   args        Map lt Integer  Point2D Double gt  map   Map of          1  new Point2D Double 1  1           2  new Point2D Double 2  2           3  new Point2D Double 3  3           4  new Point2D Double 4  4        map entrySet   forEach System out  println

User · Answer

With the newer Java versions  i e    Java 9 and forwards  you can use   Map of 1  new Point2D Double 50  50   2  new Point2D Double 100  50         generically  Map of Key1  Value1  Key2  Value2  KeyN  ValueN   Bear in mind however that Map of only works for at most 10 entries  if you have more than 10 entries that you can use   Map ofEntries entry 1  new Point2D Double 50  50    entry 2   new Point2D Double 100  50

User · Answer

There is even a better way to create a Map along with initialization   Map lt String  String gt  rightHereMap   new HashMap lt String  String gt                    put  key1    value1            put  key2    value2               For more options take a look here How can I initialise a static Map

User · Answer

Map  lt Integer  Point2D Double gt  hm   new HashMap lt Integer  Point2D gt     hm put 1  new Point2D Double 50  50

User · Answer

Java 9   public static void main String   args        Map lt Integer String gt  map   Map ofEntries entry 1  A    entry 2  B    entry 3  C

[java] Create Map in Java

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