java.lang.String.substring method is not compatible to specification

Name: saf@russia Date: 08/07/96


  
This bug was found by St.Petersburg Java SQE team (by Michael A. Gorshenev).


                      Java API Documentation
                               1.0.2
                             Par. 1.16

 " SUBSTRING

public String substring(int beginIndex, int endIndex)

      Creates a new string that is a substring of this string. The substring begins at the specified
      beginIndex and extends to the character at index endIndex - 1.

      Parameters:
            beginIndex - the beginning index, inclusive
            endIndex - the ending index, exclusive
      Returns:
            the specified substring.
      Throws
            StringIndexOutOfBoundsException (I-§1.44)
            If the beginIndex or the endIndex is out of range.
"




Bug in Java API 1.0.2

java.lang.String.substring(int, int)

   method substring() must throw IndexOutOfBoundsException if beginIndex
   is larger than endIndex but it does not.
   
=============== Here is the test fragment ===================
String s1 = "java.lang.String.substring test";

try {
  String s2 = s1.substring(16,10);
  System.out.println(s2);
}
catch (IndexOutOfBoundsException e) {
  System.out.println("Exception");
  return;
}

=============== Here is the test output =====================
String

===== Here is the part of java.lang.String source code ======

    public String substring(int beginIndex, int endIndex) {
if (beginIndex > endIndex) {
int tmp = beginIndex;
beginIndex = endIndex;
endIndex = tmp;
}
if (beginIndex < 0) {
throw new StringIndexOutOfBoundsException(beginIndex);
}
if (endIndex > count) {
throw new StringIndexOutOfBoundsException(endIndex);
}
return ((beginIndex == 0) && (endIndex == count)) ? this :
new String(offset + beginIndex, endIndex - beginIndex, value);
    }

========== Here is the part of language secification =========
===== (Pre-Release Version 1.0, Draft 5.2 - July 3, 1996) ====

20.12.32 public String substring(int beginIndex, int endIndex)
throws IndexOutOfBoundsException

The result is a newly created String object that represents a subsequence
of the character sequence represented by this String object; this
subsequence begins with the character at position beginIndex and ends
with the character at position endIndex-1. Thus, the length of the
subsequence is endIndex-beginIndex.

If beginIndex is negative, or endIndex is larger than the length of
this String object, or beginIndex is larger than endIndex, then this
method throws an IndexOutOfBoundsException.

Examples:

"hamburger".substring(4, 8) returns "urge"

"smiles".substring(1, 5) returns "mile"

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

Workaround:
None
======================================================================