Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-4491353

get & containsKey methods in java.util.Map does not work according to spec

    XMLWordPrintable

Details

    • Bug
    • Resolution: Duplicate
    • P3
    • None
    • 1.4.0
    • core-libs

    Description

      Methods get(Object key) & containsKey(Object key) in interface java.util.Map does not work according to spec when 'null' is passed as key.

      According to the documentation , method 'get(Object key)' returns the value to which this map maps the specified key.Returns 'null' if the map contains no mapping for this key.A return value of 'null' doesn't necessarily indicate that the map contains no mapping for the key, it's also possible that the map explicitly maps the key to 'null'.The 'containsKey' operation may be used to distinguish these two cases.

      In b75 when 'null' is passed as key, it's not following the spec.(b74 was working ) containsKey(null) is returning false when some value is given for key'null'.

      Given below is a testcase which explains this.

      TestCase
      ---------


       import java.util.jar.Attributes;

      public class GetTests extends Attributes {
          public static void main(String args[]) {
           GetTests status= new GetTests();
           status.getTest02();
             
      }

      /**
        * tests get with valid arguments after storing a null value
        */
          public void getTest02() {
              try {
               map.put((Attributes.Name)null,"value1");
              } catch (NullPointerException e) {
                System.out.println("Exception Thrown");
              }
              map.put(new Attributes.Name("key2"),"value2");
              map.put(new Attributes.Name("key3"),"value3");
              System.out.println("this.size() :"+this.size());
              System.out.println("containsKey : "+containsKey(null) );
              System.out.println("get((Attributes.Name)null) :"+map.get((Attributes.Name)null));
              
          }

      }

      ---------------------------------------------------------------

      TestResult with b74 :
      ---------------------
      javasoft16:/home/sa122568/Bugs/b75/GetTests 34 % java -version
      java version "1.4.0-beta_refresh"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta_refresh-b74)
      Java HotSpot(TM) Client VM (build 1.4.0-beta_refresh-b74, mixed mode)
      javasoft16:/home/sa122568/Bugs/b75/GetTests 35 % javac *.java
      javasoft16:/home/sa122568/Bugs/b75/GetTests 36 % java GetTests
      this.size() :3
      containsKey : true
      get((Attributes.Name)null) :value1


      -------------------------------------

      TestResults with b75 :
      ---------------------

      javasoft16:/home/sa122568/Bugs/b75/GetTests 41 % java -version
      java version "1.4.0-beta_refresh"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta_refresh-b75)
      Java HotSpot(TM) Client VM (build 1.4.0-beta_refresh-b75, mixed mode)
      javasoft16:/home/sa122568/Bugs/b75/GetTests 42 % javac *.java
      javasoft16:/home/sa122568/Bugs/b75/GetTests 43 % java GetTests
      this.size() :3
      containsKey : false
      get((Attributes.Name)null) :null

      ------------------------------------------------------------------------

      Attachments

        Issue Links

          Activity

            People

              mmcclosksunw Michael Mccloskey (Inactive)
              saksunw Sreejith Ak (Inactive)
              Votes:
              0 Vote for this issue
              Watchers:
              1 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:
                Imported:
                Indexed: