FULL PRODUCT VERSION :
javac 1.5.0_02


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows 2000 [Version 5.00.2195]



A DESCRIPTION OF THE PROBLEM :
With a non genericized (raw) HashMap, Map.entrySet() method return value has problem when used in an Enhanced For Loop.

If a genericized Map reference is used (e.g. Map<Object,Object>), there's no problem compiling.

The same error message output was also reproduced on SUSE 9.2 64bit with JDK 1.5.0_02 for x86_64

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The code should have compiled since the raw type of Set<Map.Entry<K,V>> should have bean Set<Map.Entry>. This should be backward compatible since it's a subclass of Set.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
    Warning: line (9) [unchecked] unchecked call to put(K,V) as a member of the raw type java.util.Map
    Error: line (11) incompatible types
                      found : java.lang.Object
                      required: java.util.Map.Entry

NOTE: the warning message is produce only with -Xlint:unchecked option

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.Map;
import java.util.HashMap;

public class TestCase
{
    public static void main(String[] args)
    {
        Map myMap = new HashMap();
        myMap.put("key1","1");

        for (Map.Entry e : myMap.entrySet())
            System.out.println("Key = "+e.getKey() + " Value = "+e.getValue());
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Workaround 1:
Using a Temporary variable, without any casting:

        Map myMap = new HashMap();
        myMap.put("key1","1");

        Set<Map.Entry> tempVar = myMap.entrySet();
        for (Map.Entry e : tempVar)
            System.out.println("Key = "+e.getKey() + " Value = "+e.getValue());

The return type is still Set instead of Set<Map.Entry>, but a warning instead of an error was produced:

    Warning: line (10) [unchecked] unchecked call to put(K,V) as a member of the raw type java.util.Map
    Warning: line (12) [unchecked] unchecked conversion
                        found : java.util.Set
                        required: java.util.Set<java.util.Map.Entry>

Workaround 2:
Use a genericized reference, the test case compiles without warnings:

        Map<Object,Object> myMap = new HashMap<Object,Object>();
        myMap.put("key1","1");

        for (Map.Entry e : myMap.entrySet())
            System.out.println("Key = "+e.getKey() + " Value = "+e.getValue());
###@###.### 2005-03-30 13:42:55 GMT