How to view the common Values between multiple keys in Same HashMap in java?

Question

HashMap<Integer,ArrayList<String>> = new HashMap<Integer,ArrayList<String>>(); 
ArrayList<constructor> frndList = new ArrayList<constructor> ();

In single hash map i will use the integer value as key and for that key i will be adding multiple values using list
now my question is key 1 having two values that same value is available in key 3 then i have to view that?

Answer 1

You have to manually loop inside your HashMap

dupl = null;
for(ek:map.keys()){
    if(ek.get(ek).contains(my_value)){
        dupl = ek.get(ek)
        break;
    }
}

if dupl is not null, you have a value in key ek

Answer 2

System.out.println("Enter first key");
    int f=scan.nextInt();
    System.out.println("Enter second key");
    int s=scan.nextInt();
    ArrayList<String> t1=new ArrayList<String>();
    ArrayList<String> t2=new ArrayList<String>();
    ArrayList<String> mf=new ArrayList<String>();
    t1.addAll(map.get(f));
    t2.addAll(map.get(s));
    for(String temp1:t1)
    {
        if(t2.contains(temp1))
        {
            mf.add(temp1);
        }
    }