ListValuedMap<String,String> listValuedMap = new ArrayListValuedHashMap(); listValuedMap.put("United States", "Washington"); listValuedMap.put("Canada", "Ottawa"); listValuedMap.put("Canada", "Ottawa"); listValuedMap.put("South Africa", "Pretoria"); listValuedMap.put("South Africa", "Cape Town"); listValuedMap.put("South Africa", "Bloemfontein"); System.out.println(listValuedMap); // Values being added to the List and allow even duplicates