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Using HashMaps, can't get 'put' method to work.

I get the error 'Cannot resolve symbol' (the symbol being the '.' after the name of the HashMap) when using the put method when trying to add entries to a HashMap. I'm using Java 2 SDK1.4 testing my scripts currently on Windows.

I've tried finding out about this error using web-searches and various Java books but I guess it must be something to do with the Java setup I'm using. Any help would be most appreciated.

Here is the code

import java.util.HashMap;

public class HashDemoGeneric {
public static void main(String[] args) {
HashMap map = new HashMap();

map.put(1, "Ian");
map.put(42, "Scott");
map.put(123, "Somebody else");

String name = map.get(42);
System.out.println(name);
}
}

zzynx

Replace:

>> map.put(1, "Ian");
>> map.put(42, "Scott");
>> map.put(123, "Somebody else");

by

map.put(new Integer(1), "Ian");
map.put(new Integer(42), "Scott");
map.put(new Integer(123), "Somebody else");

Keys and values should be objects

zzynx

and of course:

>> String name = map.get(42);

should be

String name = map.get(new Integer(42));

zzynx

Another correction:

Because get() returns just an Object, you should cast the result to a String:

String name = (String) map.get(new Integer(42));

ASKER CERTIFIED SOLUTION

zzynx

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CEHJ

If you update to the latest version of the JDK, you can use your code as is

CEHJ

>>you can use your code as is

Well, not *quite* as is, but if you upgrade, let me know

CEHJ

The following prints 'Scott'

import java.util.HashMap;

public class HashDemoGeneric {
      public static void main(String[] args) {
            HashMap<Integer, String> map = new HashMap<Integer, String>();

            map.put(1, "Ian");
            map.put(42, "Scott");
            map.put(123, "Somebody else");

            String name = map.get(42);
            System.out.println(name);
      }
}

zzynx

Thank you

patelajk

ASKER

Thanks for the help with this one! IT support in this place is non-existent as they are really understaffed. Haven't managed to update to the latest JDK yet.