Name: asR10013 Date: 06/04/2001



Java Language Specification reads:

public boolean equals(Object obj)

     Returns true if the specified object is another StackTraceElement instance representing
     the same execution point as this instance. Two stack trace elements a and b are equal if
     and only if:

          equals(a.getFileName(), b.getFileName()) &&
          a.getLineNumber() == b.getLineNumber()) &&
          equals(a.getClass(), b.getClass()) &&
          equals(a.getMethodName(), b.getMethodName())
      

     where equals is defined as:

          static boolean equals(Object a, Object b) {
              return a==b || (a != null && a.equals(b));
          }
-----------
But the sample code below shows that in some cases
method equals of class StackTraceElement
returns 'false' value instead of expected 'true'.

      
JDK : JRE1.4.0-b66
JCK : JCK1.4
Platform[s] : Windows 2000 plugin Internet Explorer 5.0
switch/Mode :
JCK test owner : http://javaweb.eng/jct/sqe/JCK-tck/usr/owners.jto
Failing Test : api/java_lang/StackTraceElement/index.html#equals

Test source location:
=====================
/net/jdk/export/disk8/local.java/jck1.4/JCK-runtime-14tests/api/java_lang/StackTraceElement/equalsTests.java

jtr file location:
==================
/net/jtgb4u4c.eng/export/sail7/JavaWebServer1.1.3/public_html/QA/merlin/b66/jck14/win32/win95_plugin_ns4.7_linux-19/workDir/api/java_lang/StackTraceElement/index_equals.jtr

How to reproduce:
====================
The following code is adopted from test source code.
Compile it and run as applet in browser.
--------------------------------------------------------------------------
import java.io.PrintWriter;

public class equalsTests extends java.applet.Applet{

    static boolean equals(Object a, Object b) {
        return a==b || (a != null && a.equals(b));
    }
    
    StackTraceElement[] getStackTraceElements(boolean mode) {
        try {
            if(mode) {throw new Throwable();} else {throw new Throwable();}
        } catch(Throwable e) {
e.printStackTrace();
            return e.getStackTrace();
        }
    }

    /* standalone interface */
    public static void main(String argv[]) {
        equalsTests test = new equalsTests();
        test.StackTraceElement2008();
    }
    
    public void init() {
StackTraceElement2008();
    }

    public void StackTraceElement2008() {
        StackTraceElement[] first = getStackTraceElements(true);
        StackTraceElement[] second = getStackTraceElements(false);
        
        for(int i = 0; i < first.length; i++) {
            for(int j = 0; j < second.length; j++) {
                boolean res1 = first[i].equals(second[j]);
                boolean res2 = equals(first[i].getFileName(), second[j].getFileName()) &&
                        (first[i].getLineNumber() == second[j].getLineNumber()) &&
                        equals(first[i].getClass(), second[j].getClass()) &&
                        equals(first[i].getMethodName(), second[j].getMethodName());
                if (res1 != res2) {
System.err.println("first["+i+"]");
System.err.println("first[i].getFileName(): "+first[i].getFileName());
System.err.println("first[i].getLineNumber(): "+first[i].getLineNumber());
System.err.println("first[i].getClass(): "+first[i].getClass());
System.err.println("first[i].getMethodName(): "+first[i].getMethodName());

System.err.println("second["+j+"]");
System.err.println("second[j].getFileName(): "+second[j].getFileName());
System.err.println("second[j].getLineNumber() :"+second[j].getLineNumber());
System.err.println("second[j].getClass() :"+second[j].getClass());
System.err.println("second[j].getMethodName() :"+second[j].getMethodName());

System.err.println("res1: "+res1+" res2: "+res2);
                    System.err.println("failedStackTraceElement.equals");
return;
                }
            }
        }
        System.err.println("OKAY");
    }
}
---------------------------------------------------------------------------
Code produces the following output:
For i=3 and j=4 according to java specification objects
should be equal, but StackTraceElement.equals returns false.
---------------------------------------------------------------------------
java.lang.Throwable
at equalsTests.getStackTraceElements(equalsTests.java:33)
at equalsTests.StackTraceElement2008(equalsTests.java:70)
at equalsTests.init(equalsTests.java:47)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
java.lang.Throwable
at equalsTests.getStackTraceElements(equalsTests.java:33)
at equalsTests.StackTraceElement2008(equalsTests.java:71)
at equalsTests.init(equalsTests.java:47)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
first[3]
first[i].getFileName(): null
first[i].getLineNumber(): -1
first[i].getClass(): class java.lang.StackTraceElement
first[i].getMethodName(): run
second[4]
second[j].getFileName(): null
second[j].getLineNumber() :-1
second[j].getClass() :class java.lang.StackTraceElement
second[j].getMethodName() :run
res1: false res2: true
failedStackTraceElement.equals
---------------------------------------------------------------------------


Test output:
=============
StackTraceElement2008: Failed. StackTraceElement.equals

Specific Machine Info:
=====================
Hostname : linux-2
Os: win2000

======================================================================