PM51629: Possible use of wrong operator to compare Strings

Interim fix 1 - Rational Application Developer for WebSphere Software, v7.5.5.5

APAR status

• Closed as program error.

Error description

• Abstract:
  
  Usage of the '==' operator to compare string values may be
  incorrect.  The equals() operation is more appropriate when
  comparing string values.
  
  Problem:
  
  Using '==' to compare two strings for equality or '!=' for
  inequality actually compares the object references rather than
  their values.
  
  Local fix:
  
  There is no known workaround at this time.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Several comparisons of strings to the empty string, in the
  form s != "" and s == "" were present in the IBM JSF Widgets
  LIbrary (JWL) source code. This comparison will behave as
  the "equals" method in most cases as an effect of String
  caching in Java, but it will not work for Strings created
  with the "new" operator or the "String.intern()" method.
  
  So far, there are no known problems or side effects of this
  expressions in the JWL components but some static analysis
  tools will prompt warnings in this regard.
  

Problem conclusion

• All String comparisons in the form s != "" and s == ""
  present in JWL source code were replaced by the safe and
  faster expressions s.length() != 0 and s.length() == 0
  respectively.
  
  Comparing the length is more efficient, in the case of empty
  strings, than using the equals method.
  
  The fix for this APAR is included in Rational Application
  Developer v7.5.5.5 iFix1.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  RATL APP DEV WI

• Fixed component ID

  5724J1901

Applicable component levels

• R700 PSN

     UP