java - Retreving the keys of Hashmap -

i trying retreive keys of hashmap

i using hashmap follows

hashmap<string, string> inner = new hashmap<string, string>(); hashmap<hashmap<string,string>, string> outer = new hashmap<hashmap<string,string>, string>(); 

i putting values in both hashmap follows:

inner.put("1","one"); inner.put("2","two"); inner.put("3","three");  outer.put(inner,"outer1"); outer.put(inner,"outer2"); 

now want output

1 1 outer1 1 one outer2 2 two outer1 2 two outer2 3 three outer1 3 three outer2 

but unable this. can please me solve this.

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edited code:

hashmap<string, string> inner = new hashmap<>();                     hashmap<string, string> inner1 = new hashmap<>();     hashmap<hashmap<string, string>, string> outer = new hashmap<>();        outer.put(inner, "outer1");      outer.put(inner1, "outer2");      inner1.put("1", "one");     inner1.put("2", "two");     inner1.put("3", "three");     inner1.put("4","three");      inner.put("1", "one");     inner.put("2", "two");     inner.put("3", "three");     inner.put("4","three");   outer.foreach((k,v) -> {     k.foreach((k1, v1) -> system.out.println(k1 + " " + v1 + " " + v)); });     } 

as mentioned in comments, second put on outer override first put (the key same in both). apart that, 1 way print out want follows:

outer.foreach((k,v) -> {     k.foreach((k1, v1) -> system.out.println(k1 + " " + v1 + " " + v)); }); 

just iterate on outer hash map , iterate again on each key (inner hashmap).

hope helps.