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Re: unchecked conversion warning.

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On 6/10/2012 9:52 PM, Broad Liyn wrote:
> 在 2012年5月30日星期三UTC+8下午9时32分43秒，（未知）写道：
>> This code compiles with an 'unchecked conversion' warning.
>> I have tried various corrections, for example casting like (Vector<Object>), but to no
>> avail.
>> What am I doing wrong?l
>> The code is the smallest demo I could make from the original application.
>>
>> import java.util.Vector;
>> public class genericsdemo
>> {
>>    private static Vector<Vector> vdata = new Vector<Vector>(); //a Vector of Vectors
>>    private static Vector<Object> vrow  = new Vector<Object>(); //a row
>>
>>    public static void main(String args[]) {
>>      vrow.add(null); //two columns in the row
>>      vrow.add(null);
>>
>>      vdata.add(vrow); //add the row to the Vector of Vectors
>>
>>      Vector vtmp = getrow(); //test
>>    }
>>
>>    private static Vector<Object> getrow() {
>>      return vdata.elementAt(0);  //warning: [unchecked] unchecked conversion
>>    }
>> }
>>
>> JensJ
> 1.vector is no longer being supported.
> 2.
>


As of JDK 7, Vector is not even deprecated.

The documentation,
http://docs.oracle.com/javase/7/docs/api/java/util/Vector.html, says "If
a thread-safe implementation is not needed, it is recommended to use
ArrayList in place of Vector." which implies that Vector might be a
reasonable choice if thread safety is needed.

Personally, I prefer to use ArrayList as base, and wrap using
Collections.synchronizedCollection, but that is not mandatory.

Patricia

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unchecked conversion warning. Jens - 2012-05-30 15:32 +0200
  Re: unchecked conversion warning. Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-05-30 13:48 +0000
    Re: unchecked conversion warning. Jens - 2012-05-30 15:52 +0200
  Re: unchecked conversion warning. Robert Klemme <shortcutter@googlemail.com> - 2012-05-30 07:54 -0700
    Re: unchecked conversion warning. Jens - 2012-05-31 22:23 +0200
      Re: unchecked conversion warning. Lew <lewbloch@gmail.com> - 2012-05-31 13:40 -0700
      Re: unchecked conversion warning. Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-05-31 16:50 -0400
        Re: unchecked conversion warning. Lew <lewbloch@gmail.com> - 2012-05-31 17:18 -0700
        Re: unchecked conversion warning. Robert Klemme <shortcutter@googlemail.com> - 2012-06-01 08:14 +0200
          Re: unchecked conversion warning. Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-01 08:48 -0400
            Re: unchecked conversion warning. Robert Klemme <shortcutter@googlemail.com> - 2012-06-01 07:32 -0700
            Re: unchecked conversion warning. Roedy Green <see_website@mindprod.com.invalid> - 2012-06-10 12:16 -0700
              Re: unchecked conversion warning. Martin Gregorie <martin@address-in-sig.invalid> - 2012-06-10 22:08 +0000
                Re: unchecked conversion warning. Lew <noone@lewscanon.com> - 2012-06-10 17:09 -0700
                Re: unchecked conversion warning. Martin Gregorie <martin@address-in-sig.invalid> - 2012-06-11 01:31 +0000
        Re: unchecked conversion warning. Jim Janney <jjanney@shell.xmission.com> - 2012-06-01 08:41 -0600
          Re: unchecked conversion warning. Patricia Shanahan <pats@acm.org> - 2012-06-01 08:44 -0700
            Re: unchecked conversion warning. markspace <-@.> - 2012-06-01 09:08 -0700
            Re: unchecked conversion warning. Gene Wirchenko <genew@ocis.net> - 2012-06-01 09:31 -0700
            Re: unchecked conversion warning. Jim Janney <jjanney@shell.xmission.com> - 2012-06-01 11:02 -0600
            Re: unchecked conversion warning. Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-01 13:54 -0400
              Re: unchecked conversion warning. Patricia Shanahan <pats@acm.org> - 2012-06-01 16:44 -0700
                Re: unchecked conversion warning. Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-01 20:24 -0400
                Re: unchecked conversion warning. Patricia Shanahan <pats@acm.org> - 2012-06-01 19:36 -0700
          Re: natural/native language capabilities (was: unchecked conversion warning.) Jim Janney <jjanney@shell.xmission.com> - 2012-06-01 11:01 -0600
        Re: unchecked conversion warning. Roedy Green <see_website@mindprod.com.invalid> - 2012-06-10 12:13 -0700
        Re: unchecked conversion warning. Arne Vajhøj <arne@vajhoej.dk> - 2012-06-20 19:28 -0400
  Re: unchecked conversion warning. Broad Liyn <broadliyn@gmail.com> - 2012-06-10 21:52 -0700
    Re: unchecked conversion warning. Lew <noone@lewscanon.com> - 2012-06-10 23:50 -0700
    Re: unchecked conversion warning. Patricia Shanahan <pats@acm.org> - 2012-06-11 00:06 -0700
      Re: unchecked conversion warning. Robert Klemme <shortcutter@googlemail.com> - 2012-06-16 15:17 +0200
        Re: unchecked conversion warning. Lew <lewbloch@gmail.com> - 2012-06-18 12:28 -0700
          Re: unchecked conversion warning. Robert Klemme <shortcutter@googlemail.com> - 2012-06-19 23:14 +0200
            Re: unchecked conversion warning. Lew <lewbloch@gmail.com> - 2012-06-19 17:15 -0700
      Re: unchecked conversion warning. Arne Vajhøj <arne@vajhoej.dk> - 2012-06-20 19:22 -0400
    Re: unchecked conversion warning. Arne Vajhøj <arne@vajhoej.dk> - 2012-06-20 19:20 -0400

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