Reduce BlockBodies download memory usage

Author: zilm13

ethereumj-core/src/main/java/org/ethereum/net/eth/message/BlockBodiesMessage.java

@@ -49,6 +49,7 @@ public BlockBodiesMessage(List<byte[]> blockBodies) {
     private synchronized void parse() {
         if (parsed) return;
         RLPList paramsList = (RLPList) RLP.decode2(encoded).get(0);
+        this.encoded = null;
 
         blockBodies = new ArrayList<>();
         for (int i = 0; i < paramsList.size(); ++i) {

ethereumj-core/src/main/java/org/ethereum/sync/BlockDownloader.java

@@ -292,11 +292,11 @@ public void onFailure(Throwable t) {
                         }
                     }
                     receivedBlocksLatch = new CountDownLatch(max(reqBlocksCounter - 2, 1));
+                    receivedBlocksLatch.await(1000, TimeUnit.MILLISECONDS);
                 } else {
                     logger.debug("{} blockRetrieveLoop: BlockQueue is full", name);
-                    receivedBlocksLatch = new CountDownLatch(1);
+                    Thread.sleep(200);
                 }
-                receivedBlocksLatch.await(200, TimeUnit.MILLISECONDS);
             } catch (InterruptedException e) {
                 break;
             } catch (Exception e) {