jodd-bean/src/main/java/jodd/bean/BeanUtilUtil.java
protected String extractIndex(final BeanProperty bp) {
		bp.index = null;
		String name = bp.name;
		int lastNdx = name.length() - 1;
		if (lastNdx < 0) {
			return null;
		}
		if (name.charAt(lastNdx) == ']') {
			int leftBracketNdx = name.lastIndexOf('[');
			if (leftBracketNdx != -1) {
				bp.setName(name.substring(0, leftBracketNdx));
				bp.index = name.substring(leftBracketNdx + 1, lastNdx);
				return bp.index;
			}
		}
		return null;
	}
protected String extractIndex(final BeanProperty bp) {
		bp.index = null;
		String name = bp.name;
		int lastNdx = name.length() - 1;
		if (lastNdx < 0) {
			return null;
		}
		if (name.charAt(lastNdx) == ']') {
			int leftBracketNdx = name.lastIndexOf('[');
			if (leftBracketNdx != -1) {
				bp.setName(name.substring(0, leftBracketNdx));
				bp.index = name.substring(leftBracketNdx + 1, lastNdx);
				return bp.index;
			}
		}
		return null;
	}
Extract index string from non-nested property name.
If index is found, it is stripped from bean property name.
If no index is found, it returns <code>null</code>.