spring-projects/spring-framework · error · InvalidPropertyException

Cannot get element with index {index} from Iterable of size

Error message

Cannot get element with index {index} from Iterable of size {currIndex}, accessed using property path '{propertyName}'

What it means

Raised in the Iterable branch when the value is an Iterable (but not a Collection, so size is unknown up front). Spring iterates looking for the element at the requested index; if the iterator is exhausted without finding it, InvalidPropertyException is thrown with 'Iterable of size {currIndex}'. currIndex reflects how many elements were actually seen.

Source

Thrown at spring-beans/src/main/java/org/springframework/beans/AbstractNestablePropertyAccessor.java:667

							if (index < 0 || index >= coll.size()) {
								throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName,
										"Cannot get element with index " + index + " from Collection of size " +
												coll.size() + ", accessed using property path '" + propertyName + "'");
							}
						}
						Iterator<Object> it = iterable.iterator();
						boolean found = false;
						int currIndex = 0;
						for (; it.hasNext(); currIndex++) {
							Object elem = it.next();
							if (currIndex == index) {
								value = elem;
								found = true;
								break;
							}
						}
						if (!found) {
							throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName,
									"Cannot get element with index " + index + " from Iterable of size " +
											currIndex + ", accessed using property path '" + propertyName + "'");
						}
					}
					else {
						throw new InvalidPropertyException(getRootClass(), this.nestedPath + propertyName,
								"Property referenced in indexed property path '" + propertyName +
										"' is neither an array nor a List/Set/Collection/Iterable nor a Map; " +
										"returned value was [" + value + "]");
					}
					indexedPropertyName.append(PROPERTY_KEY_PREFIX).append(key).append(PROPERTY_KEY_SUFFIX);
				}
			}
			return value;
		}
		catch (InvalidPropertyException ex) {
			throw ex;
		}

View on GitHub (pinned to e8729d0438)

Solutions

Use a List (or copy the Iterable into a List) when you need indexed access.
Verify the Iterable contains enough elements before indexed access.
Avoid bracket syntax on Stream-backed or lazy iterables.

Example fix

// before
public class Batch { private Iterable<Row> rows; ... } // unknown size
Object r = wrapper.getPropertyValue("rows[3]");

// after
public class Batch { private List<Row> rows = new ArrayList<>(); ... }

Defensive patterns

Strategy: validation

Validate before calling

Object it = wrapper.getPropertyValue(propertyName.replaceAll("\\[.*$", ""));
int idx = Integer.parseInt(propertyName.replaceAll(".*\\[|\\].*", ""));
if (it instanceof Collection<?> c && idx >= 0 && idx < c.size()) {
    wrapper.getPropertyValue(propertyName);
} else if (!(it instanceof Iterable)) {
    throw new IllegalArgumentException("not iterable");
}

Type guard

static boolean safeIterableIndex(Object value, int idx) {
    if (value instanceof Collection<?> c) return idx >= 0 && idx < c.size();
    return false; // non-Collection Iterable: cannot bound-check up front
}

Try / catch

try { Object v = wrapper.getPropertyValue(propertyName); }
catch (InvalidPropertyException ex) { v = null; }

Prevention

Copy custom Iterables into Lists before indexed access.
Avoid bracket syntax on Stream-backed or lazy Iterables.
Prefer List types on bean fields you intend to index.

When it happens

Trigger: getProperty("stream[5]") on an Iterable backed by a Stream or custom iterator with fewer than 6 elements; reading 'items[2]' from a Queue/deque-like Iterable with only 1 element; binding an index to a non-Collection Iterable.

Common situations: Custom Iterable types, Queue/Deque fields accessed by index; Stream-backed lazy iterables; misusing indexed access on non-List iterables.

Related errors

AI-assisted analysis of spring-projects/spring-framework@e8729d0438 (2026-08-04). Data as JSON: /data/errors/f978ed3313064555.json. Report an issue: GitHub.