FULL PRODUCT VERSION :
java version "1.8.0_40"
Java(TM) SE Runtime Environment (build 1.8.0_40-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.40-b25, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Darwin Kernel Version 13.4.0

A DESCRIPTION OF THE PROBLEM :
If the last bit (Integer.MAX_VALUE) in a BitSet is set, all attempts to fully read the stream returned by BitSet.stream() throw an IndexOutOfBoundsException.

The cause is line 1232 in BitSet.java:

next = nextSetBit(next+1)

If next is Integer.MAX_VALUE, next+1 overflows to Integer.MIN_VALUE, and nextSetBit() throws an IndexOutOfBoundsException.

The bug is also present in the current JDK 9 sources: http://hg.openjdk.java.net/jdk9/dev/jdk/file/a54a0169968c/src/java.base/share/classes/java/util/BitSet.java#l1232

Replacing line 1232 by

next = next == Integer.MAX_VALUE ? -1 : nextSetBit(next+1);

should fix this.

(By the way, this is not just a theoretical possibility. It happened in real life - I ran into it while using BitSet for a prime number sieve. Integer.MAX_VALUE is a prime number, so the bit was set.)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
BitSet b = new BitSet();
b.set(Integer.MAX_VALUE);
b.stream().count(); // throws IndexOutOfBoundsException (as many other stream methods)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
b.stream().count() should return 1 (similar for other stream methods)
ACTUAL -
b.stream().count() throws IndexOutOfBoundsException

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.lang.IndexOutOfBoundsException: fromIndex < 0: -2147483648
at java.util.BitSet.nextSetBit(BitSet.java:712)
at java.util.BitSet$1BitSetIterator.nextInt(BitSet.java:1232)
at java.util.PrimitiveIterator$OfInt.forEachRemaining(PrimitiveIterator.java:115)
at java.util.Spliterators$IntIteratorSpliterator.forEachRemaining(Spliterators.java:1908)
at java.util.Spliterator$OfInt.forEachRemaining(Spliterator.java:693)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.LongPipeline.reduce(LongPipeline.java:438)
at java.util.stream.LongPipeline.sum(LongPipeline.java:396)
at java.util.stream.IntPipeline.count(IntPipeline.java:429)
at BitSetBug.main(BitSetBug.java:7)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.BitSet;

public class BitSetBug {
  public static void main(String[] args) {
    BitSet b = new BitSet();
    b.set(Integer.MAX_VALUE);
    b.stream().count(); // throws IndexOutOfBoundsException
  }
}
---------- END SOURCE ----------