Remove spurious stack trace from singleton exception, and various minor edits

core/src/main/java/com/google/zxing/ChecksumException.java

@@ -25,6 +25,9 @@ package com.google.zxing;
 public final class ChecksumException extends ReaderException {
 
   private static final ChecksumException INSTANCE = new ChecksumException();
+  static {
+    INSTANCE.setStackTrace(NO_TRACE); // since it's meaningless
+  }
 
   private ChecksumException() {
     // do nothing

core/src/main/java/com/google/zxing/FormatException.java

@@ -26,6 +26,9 @@ package com.google.zxing;
 public final class FormatException extends ReaderException {
 
   private static final FormatException INSTANCE = new FormatException();
+  static {
+    INSTANCE.setStackTrace(NO_TRACE); // since it's meaningless
+  }
 
   private FormatException() {
   }

core/src/main/java/com/google/zxing/NotFoundException.java

@@ -25,6 +25,9 @@ package com.google.zxing;
 public final class NotFoundException extends ReaderException {
 
   private static final NotFoundException INSTANCE = new NotFoundException();
+  static {
+    INSTANCE.setStackTrace(NO_TRACE); // since it's meaningless
+  }
 
   private NotFoundException() {
     // do nothing

core/src/main/java/com/google/zxing/ReaderException.java

@@ -28,6 +28,7 @@ public abstract class ReaderException extends Exception {
   // disable stack traces when not running inside test units
   protected static final boolean isStackTrace =
       System.getProperty("surefire.test.class.path") != null;
+  protected static final StackTraceElement[] NO_TRACE = new StackTraceElement[0];
 
   ReaderException() {
     // do nothing

core/src/main/java/com/google/zxing/client/result/URIParsedResult.java

@@ -69,11 +69,9 @@ public final class URIParsedResult extends ParsedResult {
   private static String massageURI(String uri) {
     uri = uri.trim();
     int protocolEnd = uri.indexOf(':');
-    if (protocolEnd < 0) {
-      // No protocol, assume http
-      uri = "http://" + uri;
-    } else if (isColonFollowedByPortNumber(uri, protocolEnd)) {
-      // Found a colon, but it looks like it is after the host, so the protocol is still missing
+    if (protocolEnd < 0 || isColonFollowedByPortNumber(uri, protocolEnd)) {
+      // No protocol, or found a colon, but it looks like it is after the host, so the protocol is still missing,
+      // so assume http
       uri = "http://" + uri;
     }
     return uri;

core/src/test/java/com/google/zxing/oned/rss/expanded/RSSExpandedImage2resultTestCase.java

@@ -1,4 +1,4 @@
-/**
+/*
  * Copyright (C) 2010 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");

core/src/test/java/com/google/zxing/qrcode/encoder/QRCodeTestCase.java

@@ -1,4 +1,4 @@
-/**
+/*
  * Copyright 2008 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");

zxingorg/pom.xml

@@ -61,7 +61,7 @@
       <plugin>
         <groupId>org.eclipse.jetty</groupId>
         <artifactId>jetty-maven-plugin</artifactId>
-        <version>9.3.0.RC0</version>
+        <version>9.3.0.RC1</version>
       </plugin>
     </plugins>
   </build>

zxingorg/src/main/java/com/google/zxing/web/DecodeServlet.java

@@ -34,7 +34,6 @@ import com.google.zxing.common.HybridBinarizer;
 import com.google.zxing.multi.GenericMultipleBarcodeReader;
 import com.google.zxing.multi.MultipleBarcodeReader;
 
-import com.google.common.collect.Lists;
 import com.google.common.io.Resources;
 import com.google.common.net.HttpHeaders;
 import com.google.common.net.MediaType;
@@ -51,6 +50,7 @@ import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -320,7 +320,7 @@ public final class DecodeServlet extends HttpServlet {
 
     LuminanceSource source = new BufferedImageLuminanceSource(image);
     BinaryBitmap bitmap = new BinaryBitmap(new GlobalHistogramBinarizer(source));
-    Collection<Result> results = Lists.newArrayListWithCapacity(1);
+    Collection<Result> results = new ArrayList<>(1);
 
     try {
 
@@ -375,7 +375,15 @@ public final class DecodeServlet extends HttpServlet {
       }
   
       if (results.isEmpty()) {
-        handleException(savedException, request, response);
+        try {
+          throw savedException == null ? NotFoundException.getNotFoundInstance() : savedException;
+        } catch (FormatException | ChecksumException e) {
+          log.info(e.getMessage());
+          errorResponse(request, response, "format");
+        } catch (ReaderException e) { // Including NotFoundException
+          log.info(e.getMessage());
+          errorResponse(request, response, "notfound");
+        }
         return;
       }
 
@@ -402,25 +410,6 @@ public final class DecodeServlet extends HttpServlet {
     }
   }
 
-  private static void handleException(ReaderException re,
-                                      HttpServletRequest request,
-                                      HttpServletResponse response)
-      throws IOException, ServletException {
-    if (re instanceof NotFoundException) {
-      log.info("Not found: " + re);
-      errorResponse(request, response, "notfound");
-    } else if (re instanceof FormatException) {
-      log.info("Format problem: " + re);
-      errorResponse(request, response, "format");
-    } else if (re instanceof ChecksumException) {
-      log.info("Checksum problem: " + re);
-      errorResponse(request, response, "format");
-    } else {
-      log.info("Unknown problem: " + re);
-      errorResponse(request, response, "notfound");
-    }
-  }
-
   private static void errorResponse(HttpServletRequest request,
                                     HttpServletResponse response,
                                     String key) throws ServletException, IOException {