[bugfix] Analyzed FindBugs report & fixed several SEVERE issues

src/org/exist/http/RESTServer.java

@@ -1689,7 +1689,7 @@ private void writeResourceAs(final DocumentImpl resource, final DBBroker broker,
             serializer.reset();
 
             //setup the http context
-            final HttpContext httpContext = serializer.new HttpContext();
+            final HttpContext httpContext = new HttpContext();
             final HttpRequestWrapper reqw = new HttpRequestWrapper(request, formEncoding, containerEncoding);
             httpContext.setRequest(reqw);
             httpContext.setSession(reqw.getSession(false));

src/org/exist/storage/BrokerPool.java

@@ -1604,7 +1604,10 @@ public DBBroker get(final Optional<Subject> subject) throws EXistException {
             try {
                 LOG.debug("Db instance is in service mode. Waiting for db to become available again ...");
                 wait();
-            } catch(final InterruptedException e) {
+            }
+            catch(final InterruptedException e) {
+                Thread.currentThread().interrupt();
+                LOG.error("Interrupt detected");
             }
         }
 

src/org/exist/storage/NativeValueIndex.java

@@ -1156,7 +1156,7 @@ private final static class ExactMatcher implements TermMatcher {
 
         @Override
         public boolean matches(final CharSequence term) {
-            return term.toString().equals(expr);
+            return term != null && term.toString().equals(expr);
         }
     }
 
@@ -1170,7 +1170,7 @@ private final static class ContainsMatcher implements TermMatcher {
 
         @Override
         public boolean matches(final CharSequence term) {
-            return term.toString().contains(expr);
+            return term != null && term.toString().contains(expr);
         }
     }
 
@@ -1184,7 +1184,7 @@ private final static class StartsWithMatcher implements TermMatcher {
 
         @Override
         public boolean matches(final CharSequence term) {
-            return (term.toString().startsWith(expr));
+            return term != null && term.toString().startsWith(expr);
         }
     }
 
@@ -1197,7 +1197,7 @@ private final static class EndsWithMatcher implements TermMatcher {
 
         @Override
         public boolean matches(final CharSequence term) {
-            return term.toString().endsWith(expr);
+            return term != null && term.toString().endsWith(expr);
         }
     }
 

src/org/exist/storage/journal/FileSyncThread.java

@@ -41,7 +41,7 @@ public class FileSyncThread extends Thread {
 
 	// guarded by latch
     private FileChannel endOfLog;
-    private Object latch;
+    private final Object latch;
 
     // guarded by this
     private boolean syncTriggered = false;

src/org/exist/storage/journal/Journal.java

@@ -71,7 +71,7 @@
  */
 @ConfigurationClass("journal")
 //TODO: conf.xml refactoring <recovery> => <recovery><journal/></recovery>
-public class Journal {
+public final class Journal {
     /**
      * Logger for this class
      */
@@ -167,7 +167,7 @@ public Journal(final BrokerPool pool, final Path directory) throws EXistExceptio
         currentBuffer = ByteBuffer.allocateDirect(1024 * 1024);
 
         syncThread = new FileSyncThread(latch);
-        syncThread.start();
+        syncThread.start(); //this makes us to use class as a final only - no inheritance allowed
 
         this.syncOnCommit = pool.getConfiguration().getProperty(PROPERTY_RECOVERY_SYNC_ON_COMMIT, DEFAULT_SYNC_ON_COMMIT);
         if (LOG.isDebugEnabled()) {

src/org/exist/storage/lock/ReentrantReadWriteLock.java

@@ -195,7 +195,7 @@ public boolean acquire(int mode) throws LockException {
     }
 
     public synchronized void wakeUp() {
-        notify();
+        notifyAll();
     }
 
     public boolean attempt(int mode) {

src/org/exist/storage/serializers/Serializer.java

@@ -193,7 +193,8 @@ public abstract class Serializer implements XMLReader {
     protected Subject user = null;
 
     protected HttpContext httpContext = null;
-    public class HttpContext
+
+    public static class HttpContext
     {
     	private RequestWrapper request = null;
     	private ResponseWrapper response = null;

src/org/exist/storage/txn/Checkpoint.java

@@ -35,8 +35,12 @@ public class Checkpoint extends AbstractLoggable {
 	private long timestamp;
 	private long storedLsn;
 
-	private final DateFormat df =
-		DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);
+	private final static DateFormat df = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);
+    private String formatDateTimeToString(Date date){
+        synchronized (df){
+            return df.format(date);
+        }
+    }
 
     public Checkpoint(final long transactionId) {
         this(null, transactionId);
@@ -69,11 +73,11 @@ public int getLogSize() {
     }
 
     public String getDateString() {
-    	return df.format(new Date(timestamp));
+    	return formatDateTimeToString(new Date(timestamp));
     }
 
     @Override
 	public String dump() {
-		return super.dump() + " - checkpoint at " + df.format(new Date(timestamp));
+		return super.dump() + " - checkpoint at " + formatDateTimeToString(new Date(timestamp));
 	}
 }