What causes "no more elements" in hibernate/hibernate-orm?

Guard every call: while (reader.hasNext()) { JsonDocumentItemType item = reader.next(); ... }

hibernate/hibernate-orm · error · NoSuchElementException

no more elements

Error message

no more elements

What it means

StringJsonDocumentReader is Hibernate's streaming pull parser for JSON strings, implementing Iterator<JsonDocumentItemType>. next() throws the standard Java NoSuchElementException when it is called after the parser has consumed the whole document (position >= limit). It signals iteration misuse by the caller, not malformed JSON.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/type/format/StringJsonDocumentReader.java:144

				if ( currentState == JsonProcessingState.STARTING_ARRAY) {
					this.processingStates.push( JsonProcessingState.ARRAY );
				}
				break;
			default:
				throw new IllegalStateException( "Unexpected JsonProcessingState " + marker );
		}
	}

	/**
	 * Returns the next item.
	 * @return the item
	 * @throws NoSuchElementException no more item available
	 * @throws IllegalStateException not a well-formed JSON string.
	 */
	@Override
	public JsonDocumentItemType next() {

		if ( !hasNext()) throw new NoSuchElementException("no more elements");

		while (hasNext()) {
			skipWhiteSpace();
			StringJsonDocumentMarker marker = StringJsonDocumentMarker.markerOf( this.jsonString.charAt( this.position++ ) );
			moveStateMachine( marker );
			switch ( marker) {
				case OBJECT_START:
					resetValueWindow();
					return JsonDocumentItemType.OBJECT_START;
				case OBJECT_END:
					resetValueWindow();
					//this.processingStates.pop(); // closing an object or a nested one.
					return JsonDocumentItemType.OBJECT_END;
				case ARRAY_START:
					resetValueWindow();
					//this.processingStates.push( JsonProcessingState.STARTING_ARRAY );
					return JsonDocumentItemType.ARRAY_START;
				case ARRAY_END:

View on GitHub (pinned to fad1729dce)

Solutions

Guard every call: while (reader.hasNext()) { JsonDocumentItemType item = reader.next(); ... }
Stop iterating as soon as the item matching the root structure (OBJECT_END/ARRAY_END) is returned instead of draining the reader
In generic traversal code that cannot track structure, wrap iteration in try/catch NoSuchElementException and treat it as end-of-stream

Example fix

// before
while (true) {
    JsonDocumentItemType item = reader.next(); // throws NoSuchElementException at end
    process(item);
}
// after
while (reader.hasNext()) {
    JsonDocumentItemType item = reader.next();
    process(item);
}

Defensive patterns

Strategy: validation

Validate before calling

if (reader.hasNext()) {
    JsonDocumentItemType item = reader.next();
    // process item
} else {
    // document fully consumed - stop
}

Try / catch

try {
    item = reader.next();
} catch (java.util.NoSuchElementException e) {
    // treat as normal end of the JSON document
    return;
}

Prevention

Always pair next() with a hasNext() check in the same iteration step
Terminate iteration on the root OBJECT_END/ARRAY_END item instead of draining the reader
Never assume next() returns null at the end - this Iterator follows the JDK contract and throws

When it happens

Trigger: Calling reader.next() when reader.hasNext() returns false: draining the iterator past the root closing '}' / ']', calling next() a second time after a first loop already exhausted it, or constructing the reader with an empty/whitespace-only string (hasNext() is false immediately because limit == 0 or only blanks remain).

Common situations: Hand-rolled while(true){ reader.next(); } loops that expect null at the end instead of checking hasNext(); off-by-one traversal that calls next() once more after receiving OBJECT_END/ARRAY_END; generic JSON-walking code reused across reader instances.

Related errors

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/0510faf8b7d5e49d. Report an issue: GitHub.