Check out example codes for "java create map". It will help you in understanding the concepts better.

Code Example 1

Map <Integer, Point2D.Double> hm = new HashMap<Integer, Point2D>();
hm.put(1, new Point2D.Double(50, 50));

Code Example 2

Map<String, String> emptyMap = Map.of();
Map<String, String> singletonMap = Map.of("key1", "value");
Map<String, String> map = Map.of("key1","value1", "key2", "value2");

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