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What is the purpose of IteratorUtils in Apache Commons Collections?

IteratorUtils is a static helper class for constructing and combining Iterator instances beyond what the JDK provides directly.

chainedIterator() - walks through several iterators back to back as one
filteredIterator() - skips elements that fail a Predicate
transformedIterator() - applies a Transformer to each element as it's returned
singletonIterator() - wraps exactly one object as an Iterator
toList() / toArray() - drains an Iterator into a concrete collection

These helpers are handy when an API only exposes an Iterator (not a full Collection), letting you still filter, transform, or combine that data without first materializing it into a List by hand.

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Which IteratorUtils method combines several iterators into one sequential pass? chainedIterator()

✓ Correct! Well done.

singletonIterator()

✗ Try again if not.

toArray()

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filteredIterator() is used to: sort elements as they are returned

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skip elements that fail a given Predicate

✓ Correct! Well done.

convert an Iterator to a List

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