--- a/jdk/src/java.base/share/classes/java/util/zip/Deflater.java	Thu Oct 15 13:56:39 2015 +0300
+++ b/jdk/src/java.base/share/classes/java/util/zip/Deflater.java	Thu Oct 15 14:41:37 2015 +0100
@@ -318,7 +318,9 @@
      * should be called in order to provide more input
      */
     public boolean needsInput() {
-        return len <= 0;
+        synchronized (zsRef) {
+            return len <= 0;
+        }
     }
 
     /**