#vulnerable code 
                             public void process() {
		Collection<BufferedElement> toRemove = new ArrayList<BufferedElement>();

		int size = arBufferedRegions.size();
		String s = null;
		StringBuilder fullContent = new StringBuilder();
		boolean fieldFound = false;
		ARBufferedRegion currentAR = null;
		ARBufferedRegion lastAR = null;
		for (int i = 0; i < size; i++) {
			currentAR = arBufferedRegions.get(i);
			s = currentAR.getTContent();
			if (fieldFound) {
				fieldFound = !(s == null || s.length() == 0 || Character
						.isWhitespace(s.charAt(0)));
			} else {
				fieldFound = s != null && s.indexOf("$") != -1;
			}
			if (fieldFound) {
				fullContent.append(s);
				toRemove.add(currentAR);
			} else {
				if (fullContent.length() > 0) {
					lastAR.setTContent(fullContent.toString());
					fullContent.setLength(0);
					toRemove.remove(lastAR);
				}
			}
			lastAR = currentAR;
		}
		if (fullContent.length() > 0) {
			lastAR.setTContent(fullContent.toString());
			fullContent.setLength(0);
			toRemove.remove(lastAR);
		}
		super.removeAll(toRemove);

	} 
                            #location 24 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                             public void process() {
		Collection<BufferedElement> toRemove = new ArrayList<BufferedElement>();
		int size = arBufferedRegions.size();
		String s = null;
		StringBuilder fullContent = new StringBuilder();
		boolean fieldFound = false;
		ARBufferedRegion currentAR = null;
		ARBufferedRegion lastAR = null;
		for (int i = 0; i < size; i++) {
			currentAR = arBufferedRegions.get(i);
			s = currentAR.getTContent();
			if (fieldFound) {
				fieldFound = !(s == null || s.length() == 0 || Character
						.isWhitespace(s.charAt(0)));
			} else {
				fieldFound = s != null && s.indexOf("$") != -1;
			}
			if (fieldFound) {
				fullContent.append(s);
				toRemove.add(currentAR);
			} else {
				update(toRemove, fullContent, lastAR);
			}
			lastAR = currentAR;
		}
		update(toRemove, fullContent, lastAR);
		super.removeAll(toRemove);

	}