Bug: calls equals(Object) on StringBuilder and String

Call to StringBuilder.equals(String)
in org.apache.lucene.demo.html.HTMLParser.addText(String)

This method calls equals(Object) on two references of different class
types and analysis suggests they will be to objects of different classes
at runtime. Further, examination of the equals methods that would be
invoked suggest that either this call will always return false, or else
the equals method is not be symmetric (which is a property required by
the contract for equals in class Object).

Rank: Scariest (1), confidence: High
Pattern: EC_UNRELATED_TYPES
Type: EC, Category: CORRECTNESS (Correctness)

Change-Id: Iba0ddd0564ceee8cf1c176aba580c279689d1068
Signed-off-by: Carsten Hammer <carsten.hammer@t-online.de>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.ua/+/173460
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Mickael Istria <mistria@redhat.com>

org.eclipse.help.base/src_demo/org/apache/lucene/demo/html/HTMLParser.java

diff --git a/org.eclipse.help.base/src_demo/org/apache/lucene/demo/html/HTMLParser.java b/org.eclipse.help.base/src_demo/org/apache/lucene/demo/html/HTMLParser.java
index f6ad4b7..1b62e11 100644
--- a/org.eclipse.help.base/src_demo/org/apache/lucene/demo/html/HTMLParser.java
+++ b/org.eclipse.help.base/src_demo/org/apache/lucene/demo/html/HTMLParser.java
@@ -126,7 +126,7 @@
       if (!inHeading || summary.length() > 0) {
         addToSummary(text);
       }
-      if (!titleComplete && !title.equals("")) {  // finished title //$NON-NLS-1$
+      if (!titleComplete && !title.toString().isEmpty()) { // finished title
         synchronized(this) {
           titleComplete = true;                   // tell waiting threads
           notifyAll();