FULL PRODUCT VERSION :
$ /cygdrive/c/Progra~1/Java/jdk1.8.0_60/bin/java -version
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
java.util.Scanner, under input of a specified length (or multiple thereof) and a pattern with fuzzy matching can return "true" to hasNext and throw a NoSuchElementException on call to next(). This violates the documented interface that if hasNext returns true a token is available.

As the attached test shows, this is not the case... Apparently a result of a fuzzy match crossing implementations 1024 byte internal buffer size.



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Execute test program below. I saw the exception with 3 java versions, including latest.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No output printed, no exceptions thrown.
ACTUAL -
dresnick@us-wkf--P-DRESN /cygdrive/u/u/dresnick/Java
$ /cygdrive/c/Progra~1/Java/jdk1.8.0_60/bin/javac Boundary.java

dresnick@us-wkf--P-DRESN /cygdrive/u/u/dresnick/Java
$ /cygdrive/c/Progra~1/Java/jdk1.8.0_60/bin/java Boundary
Caught NoSuchElementException java.util.NoSuchElementException
java.util.NoSuchElementException
        at java.util.Scanner.throwFor(Scanner.java:862)
        at java.util.Scanner.next(Scanner.java:1371)
        at Boundary.parse(Boundary.java:14)
        at Boundary.main(Boundary.java:41)
parse returned false i=1019
Caught NoSuchElementException java.util.NoSuchElementException
java.util.NoSuchElementException
        at java.util.Scanner.throwFor(Scanner.java:862)
        at java.util.Scanner.next(Scanner.java:1371)
        at Boundary.parse(Boundary.java:14)
        at Boundary.main(Boundary.java:41)
parse returned false i=1022
Caught NoSuchElementException java.util.NoSuchElementException
java.util.NoSuchElementException
        at java.util.Scanner.throwFor(Scanner.java:862)
        at java.util.Scanner.next(Scanner.java:1371)
        at Boundary.parse(Boundary.java:14)
        at Boundary.main(Boundary.java:41)
parse returned false i=2046
Caught NoSuchElementException java.util.NoSuchElementException
java.util.NoSuchElementException
        at java.util.Scanner.throwFor(Scanner.java:862)
        at java.util.Scanner.next(Scanner.java:1371)
        at Boundary.parse(Boundary.java:14)
        at Boundary.main(Boundary.java:41)
parse returned false i=4094
Caught NoSuchElementException java.util.NoSuchElementException
java.util.NoSuchElementException
        at java.util.Scanner.throwFor(Scanner.java:862)
        at java.util.Scanner.next(Scanner.java:1371)
        at Boundary.parse(Boundary.java:14)
        at Boundary.main(Boundary.java:41)
parse returned false i=8190


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.Scanner;
import java.util.NoSuchElementException;

public class Boundary {

    static private boolean parse(String data, String boundary) {
        String dataCopy = new String(data);
        try {
            Scanner scanner = new Scanner(dataCopy);
            try {
                scanner.useDelimiter("-" + boundary + "(-)?");

                while (scanner.hasNext()) {
                    String bodyPart = scanner.next();
                }
            } finally {
                if (scanner != null)
                    scanner.close();
            }
        } catch (NoSuchElementException e) {
            System.out.println("Caught NoSuchElementException " + e);
            e.printStackTrace();
            return false;
        }

        return true;
    }
    
    public static void main (String argv[]) {
        final String boundary = ";";

        for ( int i = 0; i < 10000; ++i ) {
            StringBuilder data = new StringBuilder();
            data.append("--" + boundary);
            for (int j = 0; j< i; ++j) {
                data.append(j%10);
            }

            data.append("-" + boundary + "-");
           
            boolean ret=parse(data.toString(), boundary);
            if (!ret) {
                System.out.println("parse returned " + ret + " i=" +i);
            }
        }
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Catching and ignoring the bogus NoSuchElementException.