PDFBOX-5660: catch null, as suggested by Valery Bokov; closes #398

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1931237 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/image/JPEGFactory.java

@@ -355,6 +355,10 @@ private static byte[] encodeImageToJPEGStream(BufferedImage image, float quality
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         try (ImageOutputStream ios = ImageIO.createImageOutputStream(baos))
         {
+            if (ios == null)
+            {
+                throw new IOException("ImageIO.createImageOutputStream() returned null");
+            }
             imageWriter.setOutput(ios);
 
             // add compression

tools/src/main/java/org/apache/pdfbox/tools/imageio/ImageIOUtil.java

@@ -311,6 +311,10 @@ else if ("jpeg".equalsIgnoreCase(formatName) || "jpg".equalsIgnoreCase(formatNam
 
             // write
             imageOutput = ImageIO.createImageOutputStream(output);
+            if (imageOutput == null)
+            {
+                return false;
+            }
             writer.setOutput(imageOutput);
             writer.write(null, new IIOImage(image, null, metadata), param);
         }