From c94a8c76bd204761bf6373e5d39d276aa238801c Mon Sep 17 00:00:00 2001
From: Michael Peter Christen <mc@yacy.net>
Date: Fri, 9 Jun 2017 12:50:36 +0200
Subject: [PATCH] re-added solr synchronization hack

---
 .../cora/federate/solr/connector/SolrServerConnector.java  | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/source/net/yacy/cora/federate/solr/connector/SolrServerConnector.java b/source/net/yacy/cora/federate/solr/connector/SolrServerConnector.java
index 1d14e99f7..f201e8f42 100644
--- a/source/net/yacy/cora/federate/solr/connector/SolrServerConnector.java
+++ b/source/net/yacy/cora/federate/solr/connector/SolrServerConnector.java
@@ -50,7 +50,12 @@ import org.apache.solr.common.params.CommonParams;
 public abstract class SolrServerConnector extends AbstractSolrConnector implements SolrConnector {
 
     protected final static ConcurrentLog log = new ConcurrentLog(SolrServerConnector.class.getName());
-
+    public final static org.apache.lucene.analysis.CharArrayMap<Byte> classLoaderSynchro = new org.apache.lucene.analysis.CharArrayMap<Byte>(0, true);
+    // pre-instantiate this object to prevent sun.misc.Launcher$AppClassLoader deadlocks
+    // this is a very nasty problem; solr instantiates objects dynamically which can cause deadlocks
+    static {
+        assert classLoaderSynchro != null;
+    }
     protected SolrClient server;
 
     protected SolrServerConnector() {