Now used synchronization in all close() methods to make sure all objects

are 'closed' in an ordered way

Conflicts:
	source/de/anomic/http/server/ChunkedInputStream.java
	source/de/anomic/http/server/ChunkedOutputStream.java
	source/de/anomic/http/server/ContentLengthInputStream.java
	source/net/yacy/cora/protocol/Domains.java
	source/net/yacy/cora/services/federated/solr/SolrShardingConnector.java
	source/net/yacy/cora/services/federated/solr/SolrSingleConnector.java
	source/net/yacy/document/content/dao/PhpBB3Dao.java
	source/net/yacy/document/parser/html/AbstractTransformer.java
	source/net/yacy/kelondro/blob/BEncodedHeap.java
	source/net/yacy/kelondro/blob/HeapReader.java
	source/net/yacy/kelondro/index/RAMIndexCluster.java
	source/net/yacy/kelondro/io/ByteCountInputStream.java
	source/net/yacy/kelondro/logging/ConsoleOutErrHandler.java
	source/net/yacy/kelondro/table/SQLTable.java

source/de/anomic/crawler/CrawlQueues.java

@@ -98,7 +98,7 @@ public class CrawlQueues {
         this.delegatedURL = new ZURL(this.sb.indexSegments.segment(PROCESS).getSolr(), newQueuePath, DELEGATED_DB_FILENAME, true, this.sb.useTailCache, this.sb.exceed134217727);
     }
 
-    public void close() {
+    public synchronized void close() {
         // wait for all workers to finish
         for (final Loader w: this.workers.values()) {
             w.interrupt();

source/de/anomic/crawler/CrawlStacker.java

@@ -121,7 +121,7 @@ public final class CrawlStacker {
         this.slowQueue.announceShutdown();
     }
 
-    public void close() {
+    public synchronized void close() {
         this.log.logInfo("Shutdown. waiting for remaining " + size() + " crawl stacker job entries. please wait.");
         this.fastQueue.announceShutdown();
         this.slowQueue.announceShutdown();

source/de/anomic/crawler/CrawlSwitchboard.java

@@ -541,7 +541,7 @@ public final class CrawlSwitchboard
         return hasDoneSomething;
     }
 
-    public void close() {
+    public synchronized void close() {
         this.profilesActiveCrawlsCache.clear();
         this.profilesActiveCrawls.close();
         this.profilesPassiveCrawls.close();

source/de/anomic/crawler/NoticedURL.java

@@ -91,7 +91,7 @@ public class NoticedURL {
         this.noloadStack.clear();
     }
 
-    public void close() {
+    public synchronized void close() {
         Log.logInfo("NoticedURL", "CLOSING ALL STACKS");
         if (this.coreStack != null) {
             this.coreStack.close();

source/de/anomic/data/BlogBoard.java

@@ -88,7 +88,7 @@ public class BlogBoard {
         return database.containsKey(UTF8.getBytes(key));
     }
     
-    public void close() {
+    public synchronized void close() {
         database.close();
     }
     

source/de/anomic/data/BlogBoardComments.java

@@ -81,7 +81,7 @@ public class BlogBoardComments {
         return this.database.size();
     }
 
-    public void close() {
+    public synchronized void close() {
         this.database.close();
     }
 

source/de/anomic/data/BookmarkDate.java

@@ -53,7 +53,7 @@ public class BookmarkDate {
         this.datesTable = new MapHeap(datesFile, 20, NaturalOrder.naturalOrder, 1024 * 64, 500, '_');
     }
     
-    public void close() {
+    public synchronized void close() {
         this.datesTable.close();
     }
     

source/de/anomic/data/BookmarksDB.java

@@ -113,7 +113,7 @@ public class BookmarksDB {
     // bookmarksDB's functions for 'destructing' the class
     // -----------------------------------------------------
 
-    public void close(){
+    public synchronized void close(){
         this.bookmarks.close();
         this.tags.clear();
         this.dates.close();

source/de/anomic/data/MessageBoard.java

@@ -67,7 +67,7 @@ public class MessageBoard {
         return database.size();
     }
     
-    public void close() {
+    public synchronized void close() {
         database.close();
     }
     

source/de/anomic/data/UserDB.java

@@ -78,7 +78,7 @@ public final class UserDB {
         }
     }
     
-    public void close() {
+    public synchronized void close() {
         userTable.close();
     }
     

source/de/anomic/data/wiki/WikiBoard.java

@@ -100,7 +100,7 @@ public class WikiBoard {
     /**
      * Closes database files.
      */
-    public void close() {
+    public synchronized void close() {
         datbase.close();
         bkpbase.close();
     }

source/de/anomic/http/server/ChunkedInputStream.java

@@ -62,7 +62,7 @@ import java.io.UnsupportedEncodingException;
  */
 public class ChunkedInputStream extends InputStream {
     /** The inputstream that we're wrapping */
-    private InputStream in;
+    private final InputStream in;
 
     /** The chunk size */
     private int chunkSize;
@@ -110,22 +110,23 @@ public class ChunkedInputStream extends InputStream {
      *
      * @see HttpMethod#getResponseFooters()
      */
+    @Override
     public int read() throws IOException {
 
-        if (closed) {
+        if (this.closed) {
             throw new IOException("Attempted read from closed stream.");
         }
-        if (eof) {
+        if (this.eof) {
             return -1;
         }
-        if (pos >= chunkSize) {
+        if (this.pos >= this.chunkSize) {
             nextChunk();
-            if (eof) { 
+            if (this.eof) {
                 return -1;
             }
         }
-        pos++;
+        this.pos++;
-        return in.read();
+        return this.in.read();
     }
 
     /**
@@ -139,20 +140,21 @@ public class ChunkedInputStream extends InputStream {
      * @see java.io.InputStream#read(byte[], int, int)
      * @throws IOException if an IO problem occurs.
      */
+    @Override
     public int read(byte[] b, int off, int len) throws IOException {
 
-        if (closed) throw new IOException("Attempted read from closed stream.");
+        if (this.closed) throw new IOException("Attempted read from closed stream.");
-        if (eof) return -1;
+        if (this.eof) return -1;
 
-        if (pos >= chunkSize) {
+        if (this.pos >= this.chunkSize) {
             nextChunk();
-            if (eof) { 
+            if (this.eof) {
                 return -1;
             }
         }
-        len = Math.min(len, chunkSize - pos);
+        len = Math.min(len, this.chunkSize - this.pos);
-        int count = in.read(b, off, len);
+        int count = this.in.read(b, off, len);
-        pos += count;
+        this.pos += count;
         return count;
     }
 
@@ -164,6 +166,7 @@ public class ChunkedInputStream extends InputStream {
      * @see java.io.InputStream#read(byte[])
      * @throws IOException if an IO problem occurs.
      */
+    @Override
     public int read(byte[] b) throws IOException {
         return read(b, 0, b.length);
     }
@@ -173,9 +176,9 @@ public class ChunkedInputStream extends InputStream {
      * @throws IOException If an IO error occurs.
      */
     private void readCRLF() throws IOException {
-        int cr = in.read();
+        int cr = this.in.read();
         if (cr != '\r') throw new IOException("CRLF expected at end of chunk: cr != " + cr);
-        int lf = in.read();
+        int lf = this.in.read();
         if (lf != '\n') throw new IOException("CRLF expected at end of chunk: lf != " + lf);
     }
 
@@ -185,12 +188,12 @@ public class ChunkedInputStream extends InputStream {
      * @throws IOException If an IO error occurs.
      */
     private void nextChunk() throws IOException {
-        if (!bof) readCRLF();
+        if (!this.bof) readCRLF();
-        chunkSize = getChunkSizeFromInputStream(in);
+        this.chunkSize = getChunkSizeFromInputStream(this.in);
-        bof = false;
+        this.bof = false;
-        pos = 0;
+        this.pos = 0;
-        if (chunkSize == 0) {
+        if (this.chunkSize == 0) {
-            eof = true;
+            this.eof = true;
             skipTrailerHeaders();
         }
     }
@@ -307,7 +310,7 @@ public class ChunkedInputStream extends InputStream {
      */
     private void skipTrailerHeaders() throws IOException {
         for (; ;) {
-            String line = readLine(in, "US-ASCII");
+            String line = readLine(this.in, "US-ASCII");
             if ((line == null) || (line.trim().length() < 1)) break;
         }
     }
@@ -419,15 +422,16 @@ public class ChunkedInputStream extends InputStream {
      * next response without scanning.
      * @throws IOException If an IO problem occurs.
      */
-    public void close() throws IOException {
+    @Override
-        if (!closed) {
+    public synchronized void close() throws IOException {
+        if (!this.closed) {
             try {
-                if (!eof) {
+                if (!this.eof) {
                     exhaustInputStream(this);
                 }
             } finally {
-                eof = true;
+                this.eof = true;
-                closed = true;
+                this.closed = true;
             }
         }
     }

source/de/anomic/http/server/ChunkedOutputStream.java

@@ -33,7 +33,6 @@ import net.yacy.cora.document.ASCII;
 import net.yacy.cora.document.UTF8;
 import net.yacy.kelondro.util.ByteBuffer;
 import net.yacy.kelondro.util.FileUtils;
-
 import de.anomic.server.serverCore;
 
 public final class ChunkedOutputStream extends FilterOutputStream {
@@ -43,7 +42,8 @@ public final class ChunkedOutputStream extends FilterOutputStream {
         super(out);
     }
 
-    public void close() throws IOException {
+    @Override
+    public synchronized void close() throws IOException {
         if (!this.finished) this.finish();
         this.out.close();
     }
@@ -58,6 +58,7 @@ public final class ChunkedOutputStream extends FilterOutputStream {
         }
     }
 
+    @Override
     public void write(final byte[] b) throws IOException {
         if (this.finished) throw new IOException("ChunkedOutputStream already finalized.");
         if (b.length == 0) return;
@@ -69,6 +70,7 @@ public final class ChunkedOutputStream extends FilterOutputStream {
         this.out.flush();
     }
 
+    @Override
     public void write(final byte[] b, final int off, final int len) throws IOException {
         if (this.finished) throw new IOException("ChunkedOutputStream already finalized.");
         if (len == 0) return;
@@ -98,11 +100,12 @@ public final class ChunkedOutputStream extends FilterOutputStream {
 
         this.out.write(ASCII.getBytes(Integer.toHexString(len)));
         this.out.write(serverCore.CRLF);
-        FileUtils.copy(b, out, len);
+        FileUtils.copy(b, this.out, len);
         this.out.write(serverCore.CRLF);
         this.out.flush();
     }
 
+    @Override
     public void write(final int b) throws IOException {
         if (this.finished) throw new IOException("ChunkedOutputStream already finalized.");
 

source/de/anomic/http/server/ContentLengthInputStream.java

@@ -67,7 +67,7 @@ public class ContentLengthInputStream extends InputStream {
      * The maximum number of bytes that can be read from the stream. Subsequent
      * read operations will return -1.
      */
-    private long contentLength;
+    private final long contentLength;
 
     /** The current position */
     private long pos = 0;
@@ -102,14 +102,15 @@ public class ContentLengthInputStream extends InputStream {
      * primed to parse the next response.</p>
      * @throws IOException If an IO problem occurs.
      */
-    public void close() throws IOException {
+    @Override
-        if (!closed) {
+    public synchronized void close() throws IOException {
+        if (!this.closed) {
             try {
                 ChunkedInputStream.exhaustInputStream(this);
             } finally {
                 // close after above so that we don't throw an exception trying
                 // to read after closed!
-                closed = true;
+                this.closed = true;
             }
         }
     }
@@ -121,15 +122,16 @@ public class ContentLengthInputStream extends InputStream {
      * @throws IOException If an IO problem occurs
      * @see java.io.InputStream#read()
      */
+    @Override
     public int read() throws IOException {
-        if (closed) {
+        if (this.closed) {
             throw new IOException("Attempted read from closed stream.");
         }
 
-        if (pos >= contentLength) {
+        if (this.pos >= this.contentLength) {
             return -1;
         }
-        pos++;
+        this.pos++;
         return this.wrappedStream.read();
     }
 
@@ -145,20 +147,21 @@ public class ContentLengthInputStream extends InputStream {
      *
      * @throws java.io.IOException Should an error occur on the wrapped stream.
      */
+    @Override
     public int read (byte[] b, int off, int len) throws java.io.IOException {
-        if (closed) {
+        if (this.closed) {
             throw new IOException("Attempted read from closed stream.");
         }
 
-        if (pos >= contentLength) {
+        if (this.pos >= this.contentLength) {
             return -1;
         }
 
-        if (pos + len > contentLength) {
+        if (this.pos + len > this.contentLength) {
-            len = (int) (contentLength - pos);
+            len = (int) (this.contentLength - this.pos);
         }
         int count = this.wrappedStream.read(b, off, len);
-        pos += count;
+        this.pos += count;
         return count;
     }
 
@@ -170,6 +173,7 @@ public class ContentLengthInputStream extends InputStream {
      * @throws IOException If an IO problem occurs
      * @see java.io.InputStream#read(byte[])
      */
+    @Override
     public int read(byte[] b) throws IOException {
         return read(b, 0, b.length);
     }
@@ -182,20 +186,22 @@ public class ContentLengthInputStream extends InputStream {
      * @throws IOException If an error occurs while skipping bytes.
      * @see InputStream#skip(long)
      */
+    @Override
     public long skip(long n) throws IOException {
         // make sure we don't skip more bytes than are
         // still available
-        long length = Math.min(n, contentLength - pos);
+        long length = Math.min(n, this.contentLength - this.pos);
         // skip and keep track of the bytes actually skipped
         length = this.wrappedStream.skip(length);
         // only add the skipped bytes to the current position
         // if bytes were actually skipped
         if (length > 0) {
-            pos += length;
+            this.pos += length;
         }
         return length;
     }
 
+    @Override
     public int available() throws IOException {
         if (this.closed) {
             return 0;

source/de/anomic/server/serverCore.java

@@ -560,7 +560,7 @@ public final class serverCore extends AbstractBusyThread implements BusyThread {
             return this.stopped;
         }
 
-        public void close() {
+        public synchronized void close() {
             // closing the socket to the client
             if (this.controlSocket != null) try {
                 this.controlSocket.close();

source/net/yacy/cora/lod/TripleStore.java

@@ -117,7 +117,7 @@ public class TripleStore {
         return this.store.keyIterator();
     }
 
-    public void close() {
+    public synchronized void close() {
         this.store.close();
     }
 

source/net/yacy/cora/protocol/Domains.java

@@ -50,6 +50,7 @@ import net.yacy.cora.plugin.ClassProvider;
 import net.yacy.cora.storage.ARC;
 import net.yacy.cora.storage.ConcurrentARC;
 import net.yacy.cora.storage.KeyList;
+import net.yacy.kelondro.logging.Log;
 import net.yacy.kelondro.util.MemoryControl;
 
 public class Domains {
@@ -468,8 +469,8 @@ public class Domains {
         noLocalCheck = v;
     }
 
-    public static void close() {
+    public static synchronized void close() {
-        if (globalHosts != null) try {globalHosts.close();} catch (final IOException e) {}
+        if (globalHosts != null) try {globalHosts.close();} catch (final IOException e) {Log.logException(e);}
     }
 
     /**

source/net/yacy/cora/services/federated/solr/SolrRetryConnector.java

@@ -44,7 +44,7 @@ public class SolrRetryConnector implements SolrConnector {
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
         this.solrConnector.close();
     }
 

source/net/yacy/cora/services/federated/solr/SolrShardingConnector.java

@@ -57,7 +57,7 @@ public class SolrShardingConnector implements SolrConnector {
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
         for (final SolrConnector connector: this.connectors) connector.close();
     }
 

source/net/yacy/cora/services/federated/solr/SolrSingleConnector.java

@@ -115,7 +115,7 @@ public class SolrSingleConnector implements SolrConnector {
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
         try {
             this.server.commit();
         } catch (SolrServerException e) {
@@ -205,6 +205,7 @@ public class SolrSingleConnector implements SolrConnector {
         }
     }
 
+    @Override
     public void add(final Collection<SolrDoc> solrdocs) throws IOException, SolrException {
         ArrayList<SolrInputDocument> l = new ArrayList<SolrInputDocument>();
         for (SolrDoc d: solrdocs) l.add(d);

source/net/yacy/cora/storage/KeyList.java

@@ -91,7 +91,7 @@ public class KeyList implements Iterable<String> {
         }
     }
 
-    public void close() throws IOException {
+    public synchronized void close() throws IOException {
         synchronized (this.raf) {
             this.raf.close();
         }

source/net/yacy/cora/storage/ZIPReader.java

@@ -0,0 +1,91 @@
+package net.yacy.cora.storage;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.AbstractMap;
+import java.util.Enumeration;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+
+public class ZIPReader extends AbstractMap<String, ZipEntry> implements Map<String, ZipEntry>, Iterable<Map.Entry<String, ZipEntry>> {
+
+    private final Set<String> filenames;
+    private final ZipFile zipFile;
+
+    public ZIPReader(File file) throws IOException {
+        super();
+        if (!file.exists()) throw new IOException("ZIPWriter can only be used for existing files");
+        this.zipFile = new ZipFile(file);
+
+        // read all entries
+        this.filenames = new HashSet<String>();
+        final Enumeration<? extends ZipEntry> e = this.zipFile.entries();
+        while (e.hasMoreElements()) {
+            ZipEntry z = e.nextElement();
+            this.filenames.add(z.getName());
+        }
+    }
+
+    @Override
+    public Iterator<java.util.Map.Entry<String, ZipEntry>> iterator() {
+        final Enumeration<? extends ZipEntry> e = this.zipFile.entries();
+        return new Iterator<java.util.Map.Entry<String, ZipEntry>>() {
+
+            @Override
+            public boolean hasNext() {
+                return e.hasMoreElements();
+            }
+
+            @Override
+            public java.util.Map.Entry<String, ZipEntry> next() {
+                ZipEntry z = e.nextElement();
+                return new AbstractMap.SimpleImmutableEntry<String, ZipEntry>(z.getName(), z);
+            }
+
+            @Override
+            public void remove() {
+                throw new UnsupportedOperationException();
+            }
+
+        };
+    }
+
+    @Override
+    public int size() {
+        return this.zipFile.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return this.zipFile.size() == 0;
+    }
+
+    @Override
+    public boolean containsKey(Object key) {
+        return this.filenames.contains(key);
+    }
+
+    @Override
+    public ZipEntry get(Object key) {
+        return this.zipFile.getEntry((String) key);
+    }
+
+    @Override
+    public Set<String> keySet() {
+        return this.filenames;
+    }
+
+    @Override
+    public Set<java.util.Map.Entry<String, ZipEntry>> entrySet() {
+        throw new UnsupportedOperationException();
+    }
+
+    public void close() throws IOException {
+        this.zipFile.close();
+    }
+
+}

source/net/yacy/cora/storage/ZIPWriter.java

@@ -0,0 +1,62 @@
+package net.yacy.cora.storage;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.AbstractMap;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+public class ZIPWriter extends AbstractMap<String, ZipEntry> implements Map<String, ZipEntry>, Iterable<Map.Entry<String, ZipEntry>> {
+
+    private final HashMap<String, ZipEntry> backup;
+    private final ZipOutputStream zos;
+
+    public ZIPWriter(File file) throws IOException {
+        super();
+        if (file.exists()) throw new IOException("ZIPWriter can only be used for new files");
+        this.backup = new HashMap<String, ZipEntry>();
+        this.zos = new ZipOutputStream(new FileOutputStream(file));
+    }
+
+    @Override
+    public ZipEntry put(String key, ZipEntry value) {
+        assert !this.backup.containsKey(key);
+        try {
+            this.zos.putNextEntry(value);
+            this.backup.put(key, value);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    @Override
+    public ZipEntry get(Object key) {
+        return this.backup.get(key);
+    }
+
+    @Override
+    public Iterator<java.util.Map.Entry<String, ZipEntry>> iterator() {
+        return this.backup.entrySet().iterator();
+    }
+
+    @Override
+    public void clear() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Set<java.util.Map.Entry<String, ZipEntry>> entrySet() {
+        return this.backup.entrySet();
+    }
+
+    public void close() throws IOException {
+        this.zos.close();
+    }
+
+}

source/net/yacy/document/Document.java

@@ -702,7 +702,7 @@ dc_rights
         }
     }
 
-    public void close() {
+    public synchronized void close() {
         if (this.text == null) return;
 
         // try close the output stream

source/net/yacy/document/SentenceReader.java

@@ -142,7 +142,7 @@ public class SentenceReader implements Iterator<StringBuilder> {
         throw new UnsupportedOperationException();
     }
     
-    public void close() {
+    public synchronized void close() {
     	try {
     		raf.close();
     	} catch(IOException ioe) {

source/net/yacy/document/WordTokenizer.java

@@ -82,7 +82,7 @@ public class WordTokenizer implements Enumeration<StringBuilder> {
         return r;
     }
 
-    public void close() {
+    public synchronized void close() {
     	this.e.close();
     }
 
@@ -153,7 +153,7 @@ public class WordTokenizer implements Enumeration<StringBuilder> {
             return r;
         }
 
-        public void close() {
+        public synchronized void close() {
         	this.e.close();
         }
     }

source/net/yacy/document/content/dao/DatabaseConnection.java

@@ -85,7 +85,7 @@ public class DatabaseConnection {
         }
     }
     
-    public void close() {
+    public synchronized void close() {
         if (connection != null) { 
             try {
             	connection.close();

source/net/yacy/document/content/dao/ImportDump.java

@@ -100,7 +100,7 @@ public class ImportDump {
         close();
     }
     
-    public void close() {
+    public synchronized void close() {
         this.conn.close();
     }
     

source/net/yacy/document/content/dao/PhpBB3Dao.java

@@ -66,16 +66,18 @@ public class PhpBB3Dao implements Dao {
         this.users = new HashMap<Integer, String>();
     }
 
+    @Override
     protected void finalize() throws Throwable {
         close();
     }
 
+    @Override
     public Date first() {
         Statement stmt = null;
         ResultSet rs = null;
         try {
-            stmt = conn.statement();
+            stmt = this.conn.statement();
-            rs = stmt.executeQuery("select min(post_time) from " + prefix + "posts");
+            rs = stmt.executeQuery("select min(post_time) from " + this.prefix + "posts");
             if (rs.next()) {
                 return new Date(rs.getLong(1) * 1000L);
             }
@@ -89,12 +91,13 @@ public class PhpBB3Dao implements Dao {
         }
     }
 
+    @Override
     public Date latest() {
         Statement stmt = null;
         ResultSet rs = null;
         try {
-            stmt = conn.statement();
+            stmt = this.conn.statement();
-            rs = stmt.executeQuery("select max(post_time) from " + prefix + "posts");
+            rs = stmt.executeQuery("select max(post_time) from " + this.prefix + "posts");
             if (rs.next()) {
                 return new Date(rs.getLong(1) * 1000L);
             }
@@ -108,18 +111,21 @@ public class PhpBB3Dao implements Dao {
         }
     }
 
+    @Override
     public int size() throws SQLException {
-    	return this.conn.count(prefix + "posts");
+    	return this.conn.count(this.prefix + "posts");
     }
 
+    @Override
     public DCEntry get(int item) {
-        return getOne("select * from " + prefix + "posts where post_id = " + item);
+        return getOne("select * from " + this.prefix + "posts where post_id = " + item);
     }
 
+    @Override
     public BlockingQueue<DCEntry> query(int from, int until, int queueSize) {
         // define the sql query
         final StringBuilder sql = new StringBuilder(256);
-        sql.append("select * from " + prefix + "posts where post_id >= ");
+        sql.append("select * from " + this.prefix + "posts where post_id >= ");
         sql.append(from);
         if (until > from) {
             sql.append(" and post_id < ");
@@ -131,10 +137,11 @@ public class PhpBB3Dao implements Dao {
         return toQueue(sql, queueSize);
     }
 
+    @Override
     public BlockingQueue<DCEntry> query(Date from, int queueSize) {
      // define the sql query
         final StringBuilder sql = new StringBuilder(256);
-        sql.append("select * from " + prefix + "posts where post_time >= ");
+        sql.append("select * from " + this.prefix + "posts where post_time >= ");
         sql.append(from.getTime() / 1000);
         sql.append(" order by post_id");
 
@@ -147,7 +154,7 @@ public class PhpBB3Dao implements Dao {
         Statement stmt = null;
         ResultSet rs = null;
         try {
-            stmt = conn.statement();
+            stmt = this.conn.statement();
             rs = stmt.executeQuery(sql);
             if (rs.next()) {
                 try {
@@ -170,11 +177,12 @@ public class PhpBB3Dao implements Dao {
         // execute the query and push entries to a queue concurrently
         final BlockingQueue<DCEntry> queue = new ArrayBlockingQueue<DCEntry>(queueSize);
         Thread dbreader = new Thread() {
+            @Override
             public void run() {
                 Statement stmt = null;
                 ResultSet rs = null;
                 try {
-                    stmt = conn.statement();
+                    stmt = PhpBB3Dao.this.conn.statement();
                     rs = stmt.executeQuery(sql.toString());
                     while (rs.next()) {
                         try {
@@ -233,12 +241,12 @@ public class PhpBB3Dao implements Dao {
         if (nick != null) return nick;
 
         StringBuilder sql = new StringBuilder(256);
-        sql.append("select * from " + prefix + "users where user_id = ");
+        sql.append("select * from " + this.prefix + "users where user_id = ");
         sql.append(poster_id);
         Statement stmt = null;
         ResultSet rs = null;
         try {
-            stmt = conn.statement();
+            stmt = this.conn.statement();
             rs = stmt.executeQuery(sql.toString());
             if (rs.next()) nick = rs.getString("username");
             if (nick == null) nick = "";
@@ -253,6 +261,7 @@ public class PhpBB3Dao implements Dao {
         }
     }
 
+    @Override
     public int writeSurrogates(
         BlockingQueue<DCEntry> queue,
         File targetdir,
@@ -305,7 +314,8 @@ public class PhpBB3Dao implements Dao {
         return 0;
     }
 
-    public void close() {
+    @Override
+    public synchronized void close() {
         this.conn.close();
     }
 

source/net/yacy/document/importer/MediawikiImporter.java

@@ -564,7 +564,7 @@ public class MediawikiImporter extends Thread implements Importer {
             return this.bb.getBytes();
         }
 
-        public void close() {
+        public synchronized void close() {
             try {
                 this.is.close();
             } catch (final IOException e) {

source/net/yacy/document/parser/dwgParser.java

@@ -0,0 +1,390 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * this parser was copied and modified to fit into YaCy from the apache tika project
+ */
+
+
+package net.yacy.document.parser;
+
+
+import java.io.InputStream;
+
+import net.yacy.cora.document.MultiProtocolURI;
+import net.yacy.document.AbstractParser;
+import net.yacy.document.Document;
+import net.yacy.document.Parser;
+import net.yacy.kelondro.util.MemoryControl;
+
+import org.apache.poi.util.StringUtil;
+
+
+public class dwgParser extends AbstractParser implements Parser {
+
+
+    private static final String HEADER_2000_PROPERTIES_MARKER_STR = "DWGPROPS COOKIE";
+    private static final byte[] HEADER_2000_PROPERTIES_MARKER = new byte[HEADER_2000_PROPERTIES_MARKER_STR.length()];
+
+    static {
+        StringUtil.putCompressedUnicode(
+                HEADER_2000_PROPERTIES_MARKER_STR,
+                HEADER_2000_PROPERTIES_MARKER, 0);
+    }
+
+    /**
+     * How far to skip after the last standard property, before
+     *  we find any custom properties that might be there.
+     */
+    private static final int CUSTOM_PROPERTIES_SKIP = 20;
+
+    public dwgParser() {
+        super("DWG (CAD Drawing) parser (very basic)");
+        this.SUPPORTED_EXTENSIONS.add("dwg");
+        this.SUPPORTED_MIME_TYPES.add("application/dwg");
+        this.SUPPORTED_MIME_TYPES.add("applications/vnd.dwg");
+    }
+
+    @Override
+    public Document[] parse(final MultiProtocolURI location, final String mimeType, final String charset, final InputStream source) throws Parser.Failure, InterruptedException {
+
+        // check memory for parser
+        if (!MemoryControl.request(200 * 1024 * 1024, true))
+            throw new Parser.Failure("Not enough Memory available for pdf parser: " + MemoryControl.available(), location);
+        return null;
+        // First up, which version of the format are we handling?
+        /*
+        byte[] header = new byte[128];
+        IOUtils.readFully(source, header);
+        String version = new String(header, 0, 6, "US-ASCII");
+        XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
+        xhtml.startDocument();
+
+        if (version.equals("AC1015")) {
+            metadata.set(Metadata.CONTENT_TYPE, TYPE.toString());
+            if (skipTo2000PropertyInfoSection(stream, header)) {
+                get2000Props(stream,metadata,xhtml);
+            }
+        } else if (version.equals("AC1018")) {
+            metadata.set(Metadata.CONTENT_TYPE, TYPE.toString());
+            if (skipToPropertyInfoSection(stream, header)) {
+                get2004Props(stream,metadata,xhtml);
+            }
+        } else if (version.equals("AC1021") || version.equals("AC1024")) {
+            metadata.set(Metadata.CONTENT_TYPE, TYPE.toString());
+            if (skipToPropertyInfoSection(stream, header)) {
+                get2007and2010Props(stream,metadata,xhtml);
+            }
+        } else {
+            throw new TikaException(
+                    "Unsupported AutoCAD drawing version: " + version);
+        }
+
+        xhtml.endDocument();
+
+
+        String docTitle = null, docSubject = null, docAuthor = null, docPublisher = null, docKeywordStr = null;
+        if (info != null) {
+            docTitle = info.getTitle();
+            docSubject = info.getSubject();
+            docAuthor = info.getAuthor();
+            docPublisher = info.getProducer();
+            if (docPublisher == null || docPublisher.length() == 0) docPublisher = info.getCreator();
+            docKeywordStr = info.getKeywords();
+        }
+
+        if (docTitle == null || docTitle.length() == 0) {
+            docTitle = MultiProtocolURI.unescape(location.getFileName());
+        }
+
+        String[] docKeywords = null;
+        if (docKeywordStr != null) {
+            docKeywords = docKeywordStr.split(" |,");
+        }
+        if (docTitle == null) {
+            docTitle = docSubject;
+        }
+
+        byte[] contentBytes;
+
+        return new Document[]{new Document(
+                location,
+                mimeType,
+                "UTF-8",
+                this,
+                null,
+                docKeywords,
+                docTitle,
+                docAuthor,
+                docPublisher,
+                null,
+                null,
+                0.0f, 0.0f,
+                contentBytes,
+                null,
+                null,
+                null,
+                false)};
+                */
+    }
+
+    /*
+    private void get2004Props(
+            InputStream stream, Metadata metadata, XHTMLContentHandler xhtml)
+            throws IOException, TikaException, SAXException {
+       // Standard properties
+        for (int i = 0; i < HEADER_PROPERTIES_ENTRIES.length; i++) {
+            String headerValue = read2004String(stream);
+            handleHeader(i, headerValue, metadata, xhtml);
+        }
+
+        // Custom properties
+        int customCount = skipToCustomProperties(stream);
+        for (int i = 0; i < customCount; i++) {
+           String propName = read2004String(stream);
+           String propValue = read2004String(stream);
+           if(propName.length() > 0 && propValue.length() > 0) {
+              metadata.add(propName, propValue);
+           }
+        }
+    }
+
+    private String read2004String(InputStream stream) throws IOException, TikaException {
+       int stringLen = EndianUtils.readUShortLE(stream);
+
+       byte[] stringData = new byte[stringLen];
+       IOUtils.readFully(stream, stringData);
+
+       // Often but not always null terminated
+       if (stringData[stringLen-1] == 0) {
+           stringLen--;
+       }
+       String value = StringUtil.getFromCompressedUnicode(stringData, 0, stringLen);
+       return value;
+    }
+
+    // Stored as UCS2, so 16 bit "unicode"
+    private void get2007and2010Props(
+            InputStream stream, Metadata metadata, XHTMLContentHandler xhtml)
+            throws IOException, TikaException, SAXException {
+        // Standard properties
+        for (int i = 0; i < HEADER_PROPERTIES_ENTRIES.length; i++) {
+            String headerValue = read2007and2010String(stream);
+            handleHeader(i, headerValue, metadata, xhtml);
+        }
+
+        // Custom properties
+        int customCount = skipToCustomProperties(stream);
+        for (int i = 0; i < customCount; i++) {
+           String propName = read2007and2010String(stream);
+           String propValue = read2007and2010String(stream);
+           if(propName.length() > 0 && propValue.length() > 0) {
+              metadata.add(propName, propValue);
+           }
+        }
+    }
+
+    private String read2007and2010String(InputStream stream) throws IOException, TikaException {
+       int stringLen = EndianUtils.readUShortLE(stream);
+
+       byte[] stringData = new byte[stringLen * 2];
+       IOUtils.readFully(stream, stringData);
+       String value = StringUtil.getFromUnicodeLE(stringData);
+
+       // Some strings are null terminated
+       if(value.charAt(value.length()-1) == 0) {
+           value = value.substring(0, value.length()-1);
+       }
+
+       return value;
+    }
+
+    private void get2000Props(
+            InputStream stream, Metadata metadata, XHTMLContentHandler xhtml)
+            throws IOException, TikaException, SAXException {
+        int propCount = 0;
+        while(propCount < 30) {
+            int propIdx = EndianUtils.readUShortLE(stream);
+            int length = EndianUtils.readUShortLE(stream);
+            int valueType = stream.read();
+
+            if(propIdx == 0x28) {
+               // This one seems not to follow the pattern
+               length = 0x19;
+            } else if(propIdx == 90) {
+               // We think this means the end of properties
+               break;
+            }
+
+            byte[] value = new byte[length];
+            IOUtils.readFully(stream, value);
+            if(valueType == 0x1e) {
+                // Normal string, good
+                String val = StringUtil.getFromCompressedUnicode(value, 0, length);
+
+                // Is it one we can look up by index?
+                if(propIdx < HEADER_2000_PROPERTIES_ENTRIES.length) {
+                   metadata.add(HEADER_2000_PROPERTIES_ENTRIES[propIdx], val);
+                   xhtml.element("p", val);
+                } else if(propIdx == 0x012c) {
+                   int splitAt = val.indexOf('=');
+                   if(splitAt > -1) {
+                      String propName = val.substring(0, splitAt);
+                      String propVal = val.substring(splitAt+1);
+                      metadata.add(propName, propVal);
+                   }
+                }
+            } else {
+                // No idea...
+            }
+
+            propCount++;
+        }
+    }
+
+    private void handleHeader(
+            int headerNumber, String value, Metadata metadata,
+            XHTMLContentHandler xhtml) throws SAXException {
+        if(value == null || value.length() == 0) {
+            return;
+        }
+
+        String headerProp = HEADER_PROPERTIES_ENTRIES[headerNumber];
+        if(headerProp != null) {
+            metadata.set(headerProp, value);
+        }
+
+        xhtml.element("p", value);
+    }
+
+    // Grab the offset, then skip there
+    private boolean skipToPropertyInfoSection(InputStream stream, byte[] header)
+            throws IOException, TikaException {
+        // The offset is stored in the header from 0x20 onwards
+        long offsetToSection = EndianUtils.getLongLE(header, 0x20);
+        long toSkip = offsetToSection - header.length;
+        if(offsetToSection == 0){
+            return false;
+        }
+        while (toSkip > 0) {
+            byte[] skip = new byte[Math.min((int) toSkip, 0x4000)];
+            IOUtils.readFully(stream, skip);
+            toSkip -= skip.length;
+        }
+        return true;
+    }
+
+    //We think it can be anywhere...
+    private boolean skipTo2000PropertyInfoSection(InputStream stream, byte[] header)
+            throws IOException {
+       int val = 0;
+       while(val != -1) {
+          val = stream.read();
+          if(val == HEADER_2000_PROPERTIES_MARKER[0]) {
+             boolean going = true;
+             for(int i=1; i<HEADER_2000_PROPERTIES_MARKER.length && going; i++) {
+                val = stream.read();
+                if(val != HEADER_2000_PROPERTIES_MARKER[i]) going = false;
+             }
+             if(going) {
+                // Bingo, found it
+                return true;
+             }
+          }
+       }
+       return false;
+    }
+
+    private int skipToCustomProperties(InputStream stream)
+            throws IOException, TikaException {
+       // There should be 4 zero bytes next
+       byte[] padding = new byte[4];
+       IOUtils.readFully(stream, padding);
+       if(padding[0] == 0 && padding[1] == 0 &&
+             padding[2] == 0 && padding[3] == 0) {
+          // Looks hopeful, skip on
+          padding = new byte[CUSTOM_PROPERTIES_SKIP];
+          IOUtils.readFully(stream, padding);
+
+          // We should now have the count
+          int count = EndianUtils.readUShortLE(stream);
+
+          // Sanity check it
+          if(count > 0 && count < 0x7f) {
+             // Looks plausible
+             return count;
+          } else {
+             // No properties / count is too high to trust
+             return 0;
+          }
+       } else {
+          // No padding. That probably means no custom props
+          return 0;
+       }
+    }
+
+    public static void main(final String[] args) {
+        if (args.length > 0 && args[0].length() > 0) {
+            // file
+            final File dwgFile = new File(args[0]);
+            if(dwgFile.canRead()) {
+
+                System.out.println(dwgFile.getAbsolutePath());
+                final long startTime = System.currentTimeMillis();
+
+                // parse
+                final AbstractParser parser = new dwgParser();
+                Document document = null;
+                try {
+                    document = Document.mergeDocuments(null, "application/dwg", parser.parse(null, "application/dwg", null, new FileInputStream(dwgFile)));
+                } catch (final Parser.Failure e) {
+                    System.err.println("Cannot parse file " + dwgFile.getAbsolutePath());
+                    Log.logException(e);
+                } catch (final InterruptedException e) {
+                    System.err.println("Interrupted while parsing!");
+                    Log.logException(e);
+                } catch (final NoClassDefFoundError e) {
+                    System.err.println("class not found: " + e.getMessage());
+                } catch (final FileNotFoundException e) {
+                    Log.logException(e);
+                }
+
+                // statistics
+                System.out.println("\ttime elapsed: " + (System.currentTimeMillis() - startTime) + " ms");
+
+                // output
+                if (document == null) {
+                    System.out.println("\t!!!Parsing without result!!!");
+                } else {
+                    System.out.println("\tParsed text with " + document.getTextLength() + " chars of text and " + document.getAnchors().size() + " anchors");
+                    try {
+                        // write file
+                        FileUtils.copy(document.getText(), new File("parsedPdf.txt"));
+                    } catch (final IOException e) {
+                        System.err.println("error saving parsed document");
+                        Log.logException(e);
+                    }
+                }
+            } else {
+                System.err.println("Cannot read file "+ dwgFile.getAbsolutePath());
+            }
+        } else {
+            System.out.println("Please give a filename as first argument.");
+        }
+    }
+*/
+}

source/net/yacy/document/parser/html/AbstractTransformer.java

@@ -37,15 +37,18 @@ public abstract class AbstractTransformer implements Transformer {
         this.tags1  = tags1;
     }
 
+    @Override
     public boolean isTag0(final String tag) {
-        return tags0.contains(tag);
+        return this.tags0.contains(tag);
     }
 
+    @Override
     public boolean isTag1(final String tag) {
-        return tags1.contains(tag);
+        return this.tags1.contains(tag);
     }
 
     //the 'missing' method that shall be implemented:
+    @Override
     public abstract char[] transformText(char[] text);
     /* could be easily implemented as:
     {
@@ -54,18 +57,21 @@ public abstract class AbstractTransformer implements Transformer {
     */
 
     // the other methods must take into account to construct the return value correctly
+    @Override
     public char[] transformTag0(final String tagname, final Properties tagopts, final char quotechar) {
         return TransformerWriter.genTag0(tagname, tagopts, quotechar);
     }
 
+    @Override
     public char[] transformTag1(final String tagname, final Properties tagopts, final char[] text, final char quotechar) {
         return TransformerWriter.genTag1(tagname, tagopts, text, quotechar);
     }
 
-    public void close() {
+    @Override
+    public synchronized void close() {
         // free resources
-        tags0 = null;
+        this.tags0 = null;
-        tags1 = null;
+        this.tags1 = null;
     }
 
 }

source/net/yacy/document/parser/html/ContentTransformer.java

@@ -139,7 +139,7 @@ public class ContentTransformer extends AbstractTransformer implements Transform
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
         // free resources
         super.close();
     }

source/net/yacy/document/parser/html/ScraperInputStream.java

@@ -170,7 +170,7 @@ public class ScraperInputStream extends InputStream implements ScraperListener {
     }
 
     @Override
-    public void close() throws IOException {
+    public synchronized void close() throws IOException {
         if (this.writer != null) this.writer.close();
     }
 

source/net/yacy/kelondro/blob/BEncodedHeap.java

@@ -522,7 +522,8 @@ public class BEncodedHeap implements MapStore {
      * close the backen-file. Should be called explicitely to ensure that all data waiting in IO write buffers
      * are flushed
      */
-    public void close() {
+    @Override
+    public synchronized void close() {
         int s = this.size();
         File f = this.table.heapFile;
         this.table.close();

source/net/yacy/kelondro/blob/BEncodedHeapShard.java

@@ -154,7 +154,7 @@ public class BEncodedHeapShard extends AbstractMapStore implements MapStore {
     }
     
     @Override
-    public void close() {
+    public synchronized void close() {
         if (this.shard == null) return;
         
         final Iterator<MapStore> i = this.shard.values().iterator();

source/net/yacy/kelondro/blob/HeapReader.java

@@ -803,8 +803,8 @@ public class HeapReader {
             }
         }
 
-        public void close() {
+        public synchronized void close() {
-            if (this.is != null) try { this.is.close(); } catch (final IOException e) {}
+            if (this.is != null) try { this.is.close(); } catch (final IOException e) {Log.logException(e);}
             this.is = null;
         }
 

source/net/yacy/kelondro/blob/Tables.java

@@ -99,7 +99,7 @@ public class Tables implements Iterable<String> {
         heap.close();
     }
 
-    public void close() {
+    public synchronized void close() {
         for (final BEncodedHeap heap: this.tables.values()) heap.close();
         this.tables.clear();
     }

source/net/yacy/kelondro/index/BufferedObjectIndex.java

@@ -111,7 +111,7 @@ public class BufferedObjectIndex implements Index, Iterable<Row.Entry> {
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
         synchronized (this.backend) {
             try {
                 flushBuffer();

source/net/yacy/kelondro/index/HandleMap.java

@@ -434,7 +434,7 @@ public final class HandleMap implements Iterable<Row.Entry> {
             return this.map;
         }
 
-        public void close() {
+        public synchronized void close() {
             this.map.close();
         }
     }

source/net/yacy/kelondro/index/RAMIndexCluster.java

@@ -82,6 +82,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return (int) ((this.rowdef.objectOrder.cardinal(row.bytes(), 0, row.getPrimaryKeyLength()) / 17) % (this.cluster.length));
     }
 
+    @Override
     public final byte[] smallestKey() {
         final HandleSet keysort = new HandleSet(this.rowdef.primaryKeyLength, this.rowdef.objectOrder, this.cluster.length);
         synchronized (this.cluster) {
@@ -94,6 +95,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return keysort.smallestKey();
     }
 
+    @Override
     public final byte[] largestKey() {
         final HandleSet keysort = new HandleSet(this.rowdef.primaryKeyLength, this.rowdef.objectOrder, this.cluster.length);
         synchronized (this.cluster) {
@@ -115,6 +117,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return r;
     }
 
+    @Override
     public final void addUnique(final Entry row) throws RowSpaceExceededException {
         final int i = indexFor(row);
         assert i >= 0 : "i = " + i;
@@ -126,28 +129,37 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         for (final Entry row: rows) addUnique(row);
     }
 
+    @Override
     public final void clear() {
         synchronized (this.cluster) {
             for (final RAMIndex c: this.cluster) if (c != null) c.clear();
         }
     }
 
+    @Override
 	public final void close() {
-        clear();
         synchronized (this.cluster) {
-            for (final RAMIndex c: this.cluster) if (c != null) c.close();
+            for (final RAMIndex c: this.cluster) {
+                if (c != null) {
+                    //Log.logInfo("RAMIndexCluster", "Closing RAM index at " + c.getName() + " with " + c.size() + " entries ...");
+                    c.close();
+                }
+            }
         }
     }
 
+    @Override
     public final void deleteOnExit() {
         // no nothing here
     }
 
+    @Override
     public final String filename() {
         // we don't have a file name
         return null;
     }
 
+    @Override
     public final Entry get(final byte[] key, final boolean forcecopy) {
         final int i = indexFor(key);
         if (i < 0) return null;
@@ -156,8 +168,10 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return r.get(key, forcecopy);
     }
 
+    @Override
     public Map<byte[], Row.Entry> get(final Collection<byte[]> keys, final boolean forcecopy) throws IOException, InterruptedException {
         final Map<byte[], Row.Entry> map = new TreeMap<byte[], Row.Entry>(row().objectOrder);
+
         Row.Entry entry;
         for (final byte[] key: keys) {
             entry = get(key, forcecopy);
@@ -166,6 +180,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return map;
     }
 
+    @Override
     public final boolean has(final byte[] key) {
         final int i = indexFor(key);
         if (i < 0) return false;
@@ -174,6 +189,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return r.has(key);
     }
 
+    @Override
     public final CloneableIterator<byte[]> keys(final boolean up, final byte[] firstKey) {
         synchronized (this.cluster) {
             final Collection<CloneableIterator<byte[]>> col = new ArrayList<CloneableIterator<byte[]>>();
@@ -193,6 +209,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
      * @throws IOException
      * @throws RowSpaceExceededException
      */
+    @Override
     public final boolean put(final Entry row) throws RowSpaceExceededException {
         final int i = indexFor(row);
         assert i >= 0 : "i = " + i;
@@ -200,18 +217,21 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return accessArray(i).put(row);
     }
 
+    @Override
     public final boolean delete(final byte[] key) {
         final int i = indexFor(key);
         if (i < 0) return false;
         return accessArray(i).delete(key);
     }
 
+    @Override
     public final Entry remove(final byte[] key) {
         final int i = indexFor(key);
         if (i < 0) return null;
         return accessArray(i).remove(key);
     }
 
+    @Override
     public final ArrayList<RowCollection> removeDoubles() throws RowSpaceExceededException {
         final ArrayList<RowCollection> col = new ArrayList<RowCollection>();
         synchronized (this.cluster) {
@@ -225,6 +245,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return col;
     }
 
+    @Override
     public final Entry removeOne() {
         synchronized (this.cluster) {
             for (int i = 0; i < this.cluster.length; i++) {
@@ -238,6 +259,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return null;
     }
 
+    @Override
     public List<Row.Entry> top(final int count) {
         final List<Row.Entry> list = new ArrayList<Row.Entry>();
         synchronized (this.cluster) {
@@ -256,6 +278,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return list;
     }
 
+    @Override
     public final Entry replace(final Entry row) throws RowSpaceExceededException {
         final int i = indexFor(row);
         assert i >= 0 : "i = " + i;
@@ -263,10 +286,12 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return accessArray(i).replace(row);
     }
 
+    @Override
     public final Row row() {
         return this.rowdef;
     }
 
+    @Override
     @SuppressWarnings("unchecked")
     public final CloneableIterator<Entry> rows(final boolean up, final byte[] firstKey) {
         synchronized (this.cluster) {
@@ -282,10 +307,12 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         }
     }
 
+    @Override
     public final CloneableIterator<Entry> rows() {
         return rows(true, null);
     }
 
+    @Override
     public final int size() {
         int c = 0;
         synchronized (this.cluster) {
@@ -294,6 +321,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return c;
     }
 
+    @Override
     public long mem() {
         long m = 0;
         synchronized (this.cluster) {
@@ -302,6 +330,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return m;
     }
 
+    @Override
     public final boolean isEmpty() {
         synchronized (this.cluster) {
             for (final RAMIndex i: this.cluster) if (i != null && !i.isEmpty()) return false;
@@ -309,6 +338,7 @@ public final class RAMIndexCluster implements Index, Iterable<Row.Entry>, Clonea
         return true;
     }
 
+    @Override
     public final Iterator<Entry> iterator() {
         return this.rows(true, null);
     }

source/net/yacy/kelondro/io/ByteCountInputStream.java

@@ -29,7 +29,6 @@ package net.yacy.kelondro.io;
 import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
-//import java.util.HashMap;
 
 import net.yacy.kelondro.logging.Log;
 
@@ -66,12 +65,14 @@ public final class ByteCountInputStream extends FilterInputStream {
         this.byteCountAccountName = accountName;
     }
 
+    @Override
     public final int read(final byte[] b) throws IOException {
         final int readCount = super.read(b);
         if (readCount > 0) this.byteCount += readCount;
         return readCount;
     }
 
+    @Override
     public final int read(final byte[] b, final int off, final int len) throws IOException {
         try {
         final int readCount = super.read(b, off, len);
@@ -82,11 +83,13 @@ public final class ByteCountInputStream extends FilterInputStream {
         }
     }
 
+    @Override
     public final int read() throws IOException {
         this.byteCount++;
         return super.read();
     }
 
+    @Override
     public final long skip(final long len) throws IOException {
         final long skipCount = super.skip(len);
         if (skipCount > 0) this.byteCount += skipCount;
@@ -116,7 +119,8 @@ public final class ByteCountInputStream extends FilterInputStream {
 //        }
 //    }
 
-    public final void close() throws IOException {
+    @Override
+    public final synchronized void close() throws IOException {
         try {
             super.close();
         } catch (OutOfMemoryError e) {

source/net/yacy/kelondro/io/CharBuffer.java

@@ -473,7 +473,7 @@ public final class CharBuffer extends Writer {
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
         this.length = 0;
         this.offset = 0;
     	this.buffer = null; // assist with garbage collection

source/net/yacy/kelondro/logging/ConsoleOutErrHandler.java

@@ -123,6 +123,7 @@ public final class ConsoleOutErrHandler extends Handler {
     }
 
 
+    @Override
     public final void publish(final LogRecord record) {
         if (!isLoggable(record)) return;
 
@@ -134,7 +135,7 @@ public final class ConsoleOutErrHandler extends Handler {
             record.setMessage(msg);
         }
 
-        if (record.getLevel().intValue() >= splitLevel.intValue()) {
+        if (record.getLevel().intValue() >= this.splitLevel.intValue()) {
             this.stdErrHandler.publish(record);
         } else {
             this.stdOutHandler.publish(record);
@@ -142,12 +143,14 @@ public final class ConsoleOutErrHandler extends Handler {
         flush();
     }
 
+    @Override
     public void flush() {
         this.stdOutHandler.flush();
         this.stdErrHandler.flush();
     }
 
-    public void close() throws SecurityException {
+    @Override
+    public synchronized void close() throws SecurityException {
         this.stdOutHandler.close();
         this.stdErrHandler.close();
     }

source/net/yacy/kelondro/rwi/ReferenceContainerArray.java

@@ -75,7 +75,7 @@ public final class ReferenceContainerArray<ReferenceType extends Reference> {
             true);
     }
 
-    public void close() {
+    public synchronized void close() {
         this.array.close(true);
     }
 

source/net/yacy/kelondro/rwi/ReferenceContainerCache.java

@@ -101,7 +101,7 @@ public final class ReferenceContainerCache<ReferenceType extends Reference> exte
     }
 
     @Override
-    public void close() {
+    public synchronized void close() {
     	this.cache = null;
     }
 

source/net/yacy/kelondro/rwi/ReferenceIterator.java

@@ -83,7 +83,7 @@ public class ReferenceIterator <ReferenceType extends Reference> extends LookAhe
         return null;
     }
 
-    public void close() {
+    public synchronized void close() {
         if (this.blobs != null) this.blobs.close();
         this.blobs = null;
     }

source/net/yacy/kelondro/table/SQLTable.java

@@ -108,23 +108,28 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
 
     }
 
+    @Override
     public long mem() {
         return 0;
     }
 
+    @Override
     public byte[] smallestKey() {
         return null;
     }
 
+    @Override
     public byte[] largestKey() {
         return null;
     }
 
+    @Override
     public String filename() {
         return "dbtest." + this.theDBConnection.hashCode();
     }
 
-    public void close() {
+    @Override
+    public synchronized void close() {
         if (this.theDBConnection != null) try {
             this.theDBConnection.close();
         } catch (final SQLException e) {
@@ -133,6 +138,7 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         this.theDBConnection = null;
     }
 
+    @Override
     public int size() {
         int size = -1;
         try {
@@ -155,14 +161,17 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public boolean isEmpty() {
         return size() == 0;
     }
 
+    @Override
     public Row row() {
         return this.rowdef;
     }
 
+    @Override
     public boolean has(final byte[] key) {
         try {
             return (get(key, false) != null);
@@ -171,10 +180,12 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public ArrayList<RowCollection> removeDoubles() {
         return new ArrayList<RowCollection>();
     }
 
+    @Override
     public Row.Entry get(final byte[] key, final boolean forcecopy) throws IOException {
         try {
             final String sqlQuery = "SELECT value from test where hash = ?";
@@ -199,6 +210,7 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public Map<byte[], Row.Entry> get(final Collection<byte[]> keys, final boolean forcecopy) throws IOException, InterruptedException {
         final Map<byte[], Row.Entry> map = new TreeMap<byte[], Row.Entry>(row().objectOrder);
         Row.Entry entry;
@@ -209,6 +221,7 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         return map;
     }
 
+    @Override
     public Row.Entry replace(final Row.Entry row) throws IOException {
         try {
             final Row.Entry oldEntry = remove(row.getPrimaryKeyBytes());
@@ -231,6 +244,7 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public boolean put(final Row.Entry row) throws IOException {
         try {
             final String sqlQuery = "INSERT INTO test (" +
@@ -252,6 +266,7 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public synchronized void addUnique(final Row.Entry row) throws IOException {
         throw new UnsupportedOperationException();
     }
@@ -264,6 +279,7 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         throw new UnsupportedOperationException();
     }
 
+    @Override
     public Row.Entry remove(final byte[] key) throws IOException {
         PreparedStatement sqlStatement = null;
         try {
@@ -292,23 +308,28 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public boolean delete(final byte[] key) throws IOException {
         return remove(key) != null;
     }
 
+    @Override
     public Row.Entry removeOne() {
         return null;
     }
 
+    @Override
     public List<Row.Entry> top(final int count) throws IOException {
         return null;
     }
 
+    @Override
     public CloneableIterator<Row.Entry> rows(final boolean up, final byte[] startKey) throws IOException {
         // Objects are of type kelondroRow.Entry
         return null;
     }
 
+    @Override
     public Iterator<Entry> iterator() {
         try {
             return rows();
@@ -317,10 +338,12 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         }
     }
 
+    @Override
     public CloneableIterator<Row.Entry> rows() throws IOException {
         return null;
     }
 
+    @Override
     public CloneableIterator<byte[]> keys(final boolean up, final byte[] startKey) {
         // Objects are of type byte[]
         return null;
@@ -362,10 +385,12 @@ public class SQLTable implements Index, Iterable<Row.Entry> {
         return new int[]{0,0,0,0,0,0,0,0,0,0};
     }
 
+    @Override
     public void clear() {
         // do nothing
     }
 
+    @Override
     public void deleteOnExit() {
         // do nothing
     }

source/net/yacy/kelondro/util/XMLTables.java

@@ -161,7 +161,7 @@ public class XMLTables {
         return null;
     }
 
-    public void close() throws IOException {
+    public synchronized void close() throws IOException {
         commit(true);
     }
 

source/net/yacy/peers/NewsDB.java

@@ -122,7 +122,7 @@ public class NewsDB {
         }
     }
 
-    public void close() {
+    public synchronized void close() {
         if (this.news != null) this.news.close();
         this.news = null;
     }

source/net/yacy/peers/NewsQueue.java

@@ -98,7 +98,7 @@ public class NewsQueue implements Iterable<NewsDB.Record> {
         }
     }
 
-    public void close() {
+    public synchronized void close() {
         if (this.queueStack != null) this.queueStack.close();
         this.queueStack = null;
     }

source/net/yacy/peers/graphics/WebStructureGraph.java

@@ -749,7 +749,7 @@ public class WebStructureGraph
         }
     }
 
-    public void close() {
+    public synchronized void close() {
         // finish dns resolving queue
         if ( this.publicRefDNSResolvingWorker.isAlive() ) {
             log.logInfo("Waiting for the DNS Resolving Queue to terminate");

source/net/yacy/search/Switchboard.java

@@ -1551,7 +1551,7 @@ public final class Switchboard extends serverSwitch
         return this.crawler.clear();
     }
 
-    public void close() {
+    public synchronized void close() {
         this.log.logConfig("SWITCHBOARD SHUTDOWN STEP 1: sending termination signal to managed threads:");
         MemoryTracker.stopSystemProfiling();
         terminateAllThreads(true);

source/net/yacy/search/index/DocumentIndex.java

@@ -243,7 +243,7 @@ public class DocumentIndex extends Segment
      * close the index. This terminates all worker threads and then closes the segment.
      */
     @Override
-    public void close() {
+    public synchronized void close() {
         // send termination signal to worker threads
         for ( @SuppressWarnings("unused")
         final Worker element : this.worker ) {

source/net/yacy/search/index/Segment.java

@@ -303,7 +303,7 @@ public class Segment {
         return refCount;
     }
 
-    public void close() {
+    public synchronized void close() {
         this.termIndex.close();
         this.urlMetadata.close();
         this.urlCitationIndex.close();

source/net/yacy/search/index/Segments.java

@@ -176,7 +176,7 @@ public class Segments implements Iterable<Segment> {
         segment(this.process_assignment.get(process)).close();
     }
 
-    public void close() {
+    public synchronized void close() {
         if (this.segments != null) for (final Segment s: this.segments.values()) s.close();
         this.segments = null;
     }

source/org/apache/tools/tar/TarBuffer.java

@@ -436,7 +436,7 @@ public class TarBuffer {
      * current block before closing.
      * @throws IOException on error
      */
-    public void close() throws IOException {
+    public synchronized void close() throws IOException {
         if (this.debug) {
             System.err.println("TarBuffer.closeBuffer().");
         }

source/org/apache/tools/tar/TarInputStream.java

@@ -111,7 +111,7 @@ public class TarInputStream extends FilterInputStream {
      * @throws IOException on error
      */
     @Override
-    public void close() throws IOException {
+    public synchronized void close() throws IOException {
         this.buffer.close();
     }
 

source/org/apache/tools/tar/TarOutputStream.java

@@ -141,7 +141,7 @@ public class TarOutputStream extends FilterOutputStream {
      * @throws IOException on error
      */
     @Override
-    public void close() throws IOException {
+    public synchronized void close() throws IOException {
         if (!closed) {
             this.finish();
             this.buffer.close();