purge a lucene cache - possible memory leak fix

htroot/IndexControlURLs_p.java

@@ -34,6 +34,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.lucene.search.FieldCache;
+
 import net.yacy.cora.date.GenericFormatter;
 import net.yacy.cora.document.encoding.ASCII;
 import net.yacy.cora.document.id.DigestURL;
@@ -292,6 +294,7 @@ public class IndexControlURLs_p {
 
         if (post.containsKey("rebootsolr")) {
             segment.fulltext().rebootSolr();
+            FieldCache.DEFAULT.purgeAllCaches();
             sb.tables.recordAPICall(post, "IndexControlURLs_p.html", WorkTables.TABLE_API_TYPE_STEERING, "solr reboot");
         }
 

source/net/yacy/search/Switchboard.java

@@ -82,6 +82,7 @@ import java.util.zip.GZIPOutputStream;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
+import org.apache.lucene.search.FieldCache;
 import org.apache.solr.common.SolrDocument;
 import org.apache.solr.common.SolrInputDocument;
 
@@ -2028,6 +2029,7 @@ public final class Switchboard extends serverSwitch {
             if (WordCache.sizeCommonWords() > 1000) WordCache.clearCommonWords();
             Word.clearCache();
             // Domains.clear();            
+            FieldCache.DEFAULT.purgeAllCaches();
             
             // clean up image stack
             ResultImages.clearQueues();