spend CrawlQueues a fremem routine

- clears errorStack
- will not get hit often (but better little than nothing on low mem)

source/net/yacy/crawler/data/CrawlQueues.java

@@ -186,6 +186,15 @@ public class CrawlQueues {
         }
     }
 
+    public void freemem() {
+        if ((this.errorURL.stackSize() > 1)) {
+            log.warn("freemem: Cleaning Error-URLs report stack, "
+                    + this.errorURL.stackSize()
+                    + " entries on stack");
+            this.errorURL.clearStack();
+        }
+    }
+    
     public Request[] activeWorkerEntries() {
         synchronized (this.workers) {
             final Request[] e = new Request[this.workers.size()];

source/net/yacy/search/SwitchboardConstants.java

@@ -95,7 +95,7 @@ public final class SwitchboardConstants {
     public static final String CRAWLJOB_LOCAL_CRAWL                             = "50_localcrawl";
     public static final String CRAWLJOB_LOCAL_CRAWL_METHOD_START                = "coreCrawlJob";
     public static final String CRAWLJOB_LOCAL_CRAWL_METHOD_JOBCOUNT             = "coreCrawlJobSize";
-    public static final String CRAWLJOB_LOCAL_CRAWL_METHOD_FREEMEM              = null;
+    public static final String CRAWLJOB_LOCAL_CRAWL_METHOD_FREEMEM              = "freemem";
     public static final String CRAWLJOB_LOCAL_CRAWL_IDLESLEEP                   = "50_localcrawl_idlesleep";
     public static final String CRAWLJOB_LOCAL_CRAWL_BUSYSLEEP                   = "50_localcrawl_busysleep";
     // 60_remotecrawlloader