Map<String,String> treemap = new TreeMap();
treemap.put("United States", "Washington");
treemap.put("Canada", "Ottawa");
treemap.put("Canada", "Ottawa");
treemap.put("South Africa", "Pretoria");
treemap.put("South Africa", "Cape Town");
treemap.put("South Africa", "Bloemfontein");
System.out.println(treemap); // Duplicate Not allowed as it's a Map, Ordered by Keys as it's a TreeMap
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