Java Store a Connection in a HashMap

I was hoping to build a generic HashMap to use for storing a few things, one of them being a Connection Object. This is a simplified example :

Function to initialize

public Map<Object, Object> genObjectInit() {

   Map<Object, Object> genObject = new HashMap<Object, Object>();

}

Add a connection object (as an example)

public Map<Object, Object> genObjectConnect(Map<Object, Object> genObject) throws Exception {

   Connection PgSQL;

   try {
      Class.forName("org.postgresql.Driver");
      PgSQL = DriverManager.getConnection ( /* yes */ );
   } catch(Exception log) {
      throw new Exception("failed to connect");
   }

   genObject.put("PgSQL", PgSQL);

   return genObject;

}

Test if it's working at all

public void genObjectTest(Map<Object, Object> genObject) {

   genObject.put("Yes", "Yes");

   System.out.println(genObject.get("PgSQL").getClass().getName());
   genObject.get("PgSQL").close();


}

Adding the Connection to the HashMap seems to be working, the output from genObject.get("PgSQL").getClass().getName() is giving me org.postgresql.jdbc.PgConnection which I assume means it is still a Connection object but calling genObject.get("PgSQL").close(); crashes with

/yes/yes/yes.java:45: error: cannot find symbol
   genObject.get("PgSQL").close();
                         ^

I've clearly misunderstood something here. How can I use the functionality of a generically stored Connection (or equivalent but equally unique object)?

Using Map<Object, Object> gives you access to the methods declared in Object class, because when you retrieve an object from the map

public void genObjectTest(Map<Object, Object> genObject) {

   genObject.put("Yes", "Yes");

   System.out.println(genObject.get("PgSQL").getClass().getName());
   genObject.get("PgSQL").close();


}

then result of the genObject.get("PgSQL") is stored in an instance of the Object class.

Depending on your use case you could either try to use Java Generics with the specific type and declare your Map as Map<Object, Connection> like this:

    public void genObjectTest(Map<Object, Connection> genObject) {

        genObject.put("Yes", connectionInstance);

        System.out.println(genObject.get("PgSQL").getClass().getName());
        Connection pgSQL = genObject.get("PgSQL");
        try {
            pgSQL.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}

which gives you many advantages, one of them is compile-time type checks, or you could eventually do type casting when retrieving an Object like:

public void genObjectTest(Map<Object, Object> genObject) {

    genObject.put("Yes", "Yes");

    System.out.println(genObject.get("PgSQL").getClass().getName());
    Object connectionAsObject = genObject.get("PgSQL");
    if (connectionAsObject instanceof Connection) {
        Connection pgSQL = (Connection) connectionAsObject;
        try {
            pgSQL.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}

Which however is less preferred solution. With the first solution, i.e. java generics with the specific type, another advantage is that you don't have to do this type casting.