Java Map interface doesn’t provide possibility to have multiple keys for single entry. Let’s see what are the possible workarounds.

1. Implement our own MultiKey object

public class MultiKey {
    private String key1;
    private String key2;
    String[] keys;

    public MultiKey(String... keys) {
        this.keys = keys;
    }

    @Override
    public int hashCode() {
        int i = 1;
        StringBuffer keysChain = new StringBuffer();
        for (String key : keys) {
            keysChain.append("key" + i + key + "|");
            i++;
        }
        return keysChain.toString().hashCode();
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null || !(obj instanceof MultiKey)) {
            return false;
        }
        MultiKey multiKey = (MultiKey) obj;
        return Arrays.equals(multiKey.keys, this.keys);
    }
}

The important point here is to overright equals() and hashCode() methods.
The usage will be the following:

Map<MultiKey, String> nameToLocation = new HashMap<>();
nameToLocation.put(new MultiKey("Tom","Jones"), "USA");
nameToLocation.put(new MultiKey("Jose","Gonzalez", "Andreas"), "Spain");
nameToLocation.put(new MultiKey("Johan"), "Germany");
[addToAppearHere]

2. Map of Maps solution:

Map<String, Map<String, String>> multiMap = new HashMap<>();
Map<String, String> nestedMap = new HashMap<>();
nestedMap.put("Jones", "USA");
multiMap.put("Tom", nestedMap);

multiMap.get("Tom").get("Jones")

// Output: "USA"

3. Guava Table
Guava library provides Table data structure which under the hood uses Map of Maps solution. This is only when we have double keys.

Table<String, String, String> table = HashBasedTable.create();
table.put("Tom", "Jones", "USA");

// Output: "USA"

4. Apache Commons MultiKeyMap

With MultiKeyMap we can have not only two but more keys

MultiKeyMap multiKeyMap = new MultiKeyMap();
nameToLocation.put(new MultiKey("Jose","Gonzalez", "Andreas"), "Spain");

// Output: "Spain"