dictionary - Data disappearing

Question

I am trying to have a routine that holds a temporary map of data, then clears the original and puts the original data back into the map. The problem is the data is disappearing somewhere. ...

    public static void set( String dataGroup, Map<String,String> dataValues ) {
        if( dataGroup.equalsIgnoreCase( "TITLE" ) ) {
                System.out.println( "0101 roomTitles:" );
                for( String s : roomTitles.keySet() ) System.out.println( s + "=" + roomTitles.get( s ) );
                System.out.println( "0049 dataValues:" );
                for( String s : dataValues.keySet() ) System.out.println( s + "=" + dataValues.get( s ) );
                System.out.println( "roomTitles.clear()" );
            roomTitles.clear();
                System.out.println( "0057 roomTitles:" );
                for( String s : roomTitles.keySet() ) System.out.println( s + "=" + roomTitles.get( s ) );
                System.out.println( "0058 dataValues:" );
                for( String s : dataValues.keySet() ) System.out.println( s + "=" + dataValues.get( s ) );
            roomTitles = dataValues;
                System.out.println( "0052 roomTitles:" );
                for( String s : roomTitles.keySet() ) System.out.println( s + "=" + roomTitles.get( s ) );
                System.out.println();
        }
    }

I have indented the debugging lines I added trying to find the problem. The result was:

0101 roomTitles:
z(6--7s#;(=Unknown
0049 dataValues:
z(6--7s#;(=Unknown
        roomTitles.clear()
0057 roomTitles:
0058 dataValues:
0052 roomTitles:

The values in the map dataValues seems to disappear when I clear the map roomTitles. Can somebody tell me why?

Answer 1

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