HashMap with multiple values under the same key

Question

Is it possible for us to implement a HashMap with one key and two values. Just as HashMap?

Please do help me, also by telling (if there is no way) any other way to

Answer 1

Try LinkedHashMap, sample:

Map<String,String> map = new LinkedHashMap<String,String>();    
map.put('1','linked');map.put('1','hash');    
map.put('2','map');map.put('3','java');.. 

output:

keys: 1,1,2,3

values: linked,hash, map, java

Answer 2

Using Java Collectors

// Group employees by department
Map<Department, List<Employee>> byDept = employees.stream()
                    .collect(Collectors.groupingBy(Employee::getDepartment));

where Department is your key

Answer 3

String key= "services_servicename"

ArrayList<String> data;

for(int i = 0; i lessthen data.size(); i++) {
    HashMap<String, String> servicesNameHashmap = new HashMap<String, String>();
    servicesNameHashmap.put(key,data.get(i).getServiceName());
    mServiceNameArray.add(i,servicesNameHashmap);
}

I have got the Best Results.

You just have to create new HashMap like

HashMap<String, String> servicesNameHashmap = new HashMap<String, String>();

in your for loop. It will have same effect like same key and multiple values.

Answer 4

Yes and no. The solution is to build a Wrapper clas for your values that contains the 2 (3, or more) values that correspond to your key.