Question

What is the easiest way to create a HashMap like this :

( student1 => Map( name => Tim,         
                   Scores => Map( math => 10,
                                  physics => 20,
                                  Computers => 30),
                   place => Miami,
                   ranking => Array(2,8,1,13),
                ), 
student2 => Map ( 
                  ...............
                  ...............
                ),
............................
............................
);

I tried this :

HashMap record = new HashMap();
record.put("student1", new HashMap());
record.get("student1").put("name","Tim");
record.get("student1").put("Scores", new HashMap());

But I get error. I do it that way because, record.get("student1") is a HashMap object, so I assume a put on that should work, and so on.

If it doesnt work, what is the best way to do it ?

Answer 1

You get that exception because get() returns a type Object. you need to cast that to a Map.

((Map)record.get("student1")).put("name","Tim");