Fix IndexOutOfBoundsException and avoid instantiating AppsPathInfo mu…

…ltiple times

common/network-common/src/main/java/org/apache/spark/network/protocol/Encoders.java

@@ -62,6 +62,7 @@ public static void encode(ByteBuf buf, RoaringBitmap b) {
       // RoaringBitmap requires nio ByteBuffer for serde. We expose the netty ByteBuf as a nio
       // ByteBuffer. Here, we need to explicitly manage the index so we can write into the
       // ByteBuffer, and the write is reflected in the underneath ByteBuf.
+      buf.ensureWritable(encodedLength);
       b.serialize(buf.nioBuffer(buf.writerIndex(), encodedLength));
       buf.writerIndex(buf.writerIndex() + encodedLength);
     }

common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/RemoteBlockPushResolver.java

@@ -417,7 +417,7 @@ public void registerExecutor(String appId, ExecutorShuffleInfo executorInfo) {
         + "num sub-dirs {}", appId, Arrays.toString(executorInfo.localDirs),
           executorInfo.subDirsPerLocalDir);
     }
-    appsPathInfo.putIfAbsent(appId, new AppPathsInfo(appId, executorInfo.localDirs,
+    appsPathInfo.computeIfAbsent(appId, id -> new AppPathsInfo(appId, executorInfo.localDirs,
       executorInfo.subDirsPerLocalDir));
   }