[SPARK-53064][CORE] Rewrite MDC LogKey in Java

### What changes were proposed in this pull request?

This PR proposes to rewrite a few classes used by the Structured Logging API from Scala to Java.

### Why are the changes needed?

Previously (before 3.5), modules under `common` were pure Java, and were easy to embed into other services, for example, the YARN External Shuffle Service will be run as a plugin of the YARN Resource Manager daemon process. With recent years' changes, some pure Java modules also require `scala-library` to be present at runtime, i.e., SPARK-52942 reports that YARN ESS causes YARN RM to fail to start due to missing `scala-library` in the classpath.

Instead of bundling `scala-library` into YARN ESS jar, #51650 (comment) suggests making it scala-free again.

This also makes Java's invocation of Structured Logging API much cleaner, now, it can be called without ugly `$.MODULE$`.
```patch
- MDC.of(LogKeys.HOST_PORT$.MODULE$, address);
+ MDC.of(LogKeys.HOST_PORT, address);
```

### Does this PR introduce _any_ user-facing change?

No, they are internal APIs, for those plugin developers who want to provide custom `LogKey`s, there still possible to make it compatible with both Spark 4.0 and the new API proposed by this PR, see https://github.com/pan3793/SPARK-53064

```java
import org.apache.spark.internal.LogKey;

// CUSTOM_LOG_KEY is compatible with both Spark 4.0 and SPARK-53064
public class JavaCustomLogKeys {
  // Custom `LogKey` must be `implements LogKey`
  public static class CUSTOM_LOG_KEY implements LogKey {
    Override
    public String name() {
      return "custom_log_key";
    }
  }

  // Singleton
  public static final CUSTOM_LOG_KEY CUSTOM_LOG_KEY = new CUSTOM_LOG_KEY();
}
```

### How was this patch tested?

Pass GHA, and verified YARN ESS works without `scala-library`.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #51775 from pan3793/SPARK-53064.

Authored-by: Cheng Pan <[email protected]>
Signed-off-by: yangjie01 <[email protected]>

Author: pan3793

common/network-common/src/main/java/org/apache/spark/network/client/TransportClient.java

@@ -364,8 +364,8 @@ public void operationComplete(Future<? super Void> future) throws Exception {
         }
       } else {
         logger.error("Failed to send RPC {} to {}", future.cause(),
-            MDC.of(LogKeys.REQUEST_ID$.MODULE$, requestId),
-            MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+            MDC.of(LogKeys.REQUEST_ID, requestId),
+            MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
         channel.close();
         try {
           String errorMsg = String.format("Failed to send RPC %s to %s: %s", requestId,

common/network-common/src/main/java/org/apache/spark/network/client/TransportClientFactory.java

@@ -193,9 +193,9 @@ public TransportClient createClient(String remoteHost, int remotePort, boolean f
     final String resolvMsg = resolvedAddress.isUnresolved() ? "failed" : "succeed";
     if (hostResolveTimeMs > 2000) {
       logger.warn("DNS resolution {} for {} took {} ms",
-        MDC.of(LogKeys.STATUS$.MODULE$, resolvMsg),
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, resolvedAddress),
-        MDC.of(LogKeys.TIME$.MODULE$, hostResolveTimeMs));
+        MDC.of(LogKeys.STATUS, resolvMsg),
+        MDC.of(LogKeys.HOST_PORT, resolvedAddress),
+        MDC.of(LogKeys.TIME, hostResolveTimeMs));
     } else {
       logger.trace("DNS resolution {} for {} took {} ms",
           resolvMsg, resolvedAddress, hostResolveTimeMs);
@@ -210,7 +210,7 @@ public TransportClient createClient(String remoteHost, int remotePort, boolean f
           return cachedClient;
         } else {
           logger.info("Found inactive connection to {}, creating a new one.",
-            MDC.of(LogKeys.HOST_PORT$.MODULE$, resolvedAddress));
+            MDC.of(LogKeys.HOST_PORT, resolvedAddress));
         }
       }
       // If this connection should fast fail when last connection failed in last fast fail time
@@ -314,7 +314,7 @@ public void operationComplete(final Future<Channel> handshakeFuture) {
               logger.debug("{} successfully completed TLS handshake to ", address);
             } else {
               logger.info("failed to complete TLS handshake to {}", handshakeFuture.cause(),
-                MDC.of(LogKeys.HOST_PORT$.MODULE$, address));
+                MDC.of(LogKeys.HOST_PORT, address));
               cf.channel().close();
             }
           }
@@ -340,17 +340,17 @@ public void operationComplete(final Future<Channel> handshakeFuture) {
     } catch (Exception e) { // catch non-RuntimeExceptions too as bootstrap may be written in Scala
       long bootstrapTimeMs = (System.nanoTime() - preBootstrap) / 1000000;
       logger.error("Exception while bootstrapping client after {} ms", e,
-        MDC.of(LogKeys.BOOTSTRAP_TIME$.MODULE$, bootstrapTimeMs));
+        MDC.of(LogKeys.BOOTSTRAP_TIME, bootstrapTimeMs));
       client.close();
       Throwables.throwIfUnchecked(e);
       throw new RuntimeException(e);
     }
     long postBootstrap = System.nanoTime();
 
     logger.info("Successfully created connection to {} after {} ms ({} ms spent in bootstraps)",
-      MDC.of(LogKeys.HOST_PORT$.MODULE$, address),
-      MDC.of(LogKeys.ELAPSED_TIME$.MODULE$, (postBootstrap - preConnect) / 1000000),
-      MDC.of(LogKeys.BOOTSTRAP_TIME$.MODULE$, (postBootstrap - preBootstrap) / 1000000));
+      MDC.of(LogKeys.HOST_PORT, address),
+      MDC.of(LogKeys.ELAPSED_TIME, (postBootstrap - preConnect) / 1000000),
+      MDC.of(LogKeys.BOOTSTRAP_TIME, (postBootstrap - preBootstrap) / 1000000));
 
     return client;
   }

common/network-common/src/main/java/org/apache/spark/network/client/TransportResponseHandler.java

@@ -145,8 +145,8 @@ public void channelInactive() {
     if (hasOutstandingRequests()) {
       String remoteAddress = getRemoteAddress(channel);
       logger.error("Still have {} requests outstanding when connection from {} is closed",
-        MDC.of(LogKeys.COUNT$.MODULE$, numOutstandingRequests()),
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, remoteAddress));
+        MDC.of(LogKeys.COUNT, numOutstandingRequests()),
+        MDC.of(LogKeys.HOST_PORT, remoteAddress));
       failOutstandingRequests(new IOException("Connection from " + remoteAddress + " closed"));
     }
   }
@@ -156,8 +156,8 @@ public void exceptionCaught(Throwable cause) {
     if (hasOutstandingRequests()) {
       String remoteAddress = getRemoteAddress(channel);
       logger.error("Still have {} requests outstanding when connection from {} is closed",
-        MDC.of(LogKeys.COUNT$.MODULE$, numOutstandingRequests()),
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, remoteAddress));
+        MDC.of(LogKeys.COUNT, numOutstandingRequests()),
+        MDC.of(LogKeys.HOST_PORT, remoteAddress));
       failOutstandingRequests(cause);
     }
   }
@@ -168,8 +168,8 @@ public void handle(ResponseMessage message) throws Exception {
       ChunkReceivedCallback listener = outstandingFetches.get(resp.streamChunkId);
       if (listener == null) {
         logger.warn("Ignoring response for block {} from {} since it is not outstanding",
-          MDC.of(LogKeys.STREAM_CHUNK_ID$.MODULE$, resp.streamChunkId),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+          MDC.of(LogKeys.STREAM_CHUNK_ID, resp.streamChunkId),
+          MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
         resp.body().release();
       } else {
         outstandingFetches.remove(resp.streamChunkId);
@@ -180,9 +180,9 @@ public void handle(ResponseMessage message) throws Exception {
       ChunkReceivedCallback listener = outstandingFetches.get(resp.streamChunkId);
       if (listener == null) {
         logger.warn("Ignoring response for block {} from {} ({}) since it is not outstanding",
-          MDC.of(LogKeys.STREAM_CHUNK_ID$.MODULE$, resp.streamChunkId),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)),
-          MDC.of(LogKeys.ERROR$.MODULE$, resp.errorString));
+          MDC.of(LogKeys.STREAM_CHUNK_ID, resp.streamChunkId),
+          MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)),
+          MDC.of(LogKeys.ERROR, resp.errorString));
       } else {
         outstandingFetches.remove(resp.streamChunkId);
         listener.onFailure(resp.streamChunkId.chunkIndex(), new ChunkFetchFailureException(
@@ -192,9 +192,9 @@ public void handle(ResponseMessage message) throws Exception {
       RpcResponseCallback listener = (RpcResponseCallback) outstandingRpcs.get(resp.requestId);
       if (listener == null) {
         logger.warn("Ignoring response for RPC {} from {} ({} bytes) since it is not outstanding",
-          MDC.of(LogKeys.REQUEST_ID$.MODULE$, resp.requestId),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)),
-          MDC.of(LogKeys.RESPONSE_BODY_SIZE$.MODULE$, resp.body().size()));
+          MDC.of(LogKeys.REQUEST_ID, resp.requestId),
+          MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)),
+          MDC.of(LogKeys.RESPONSE_BODY_SIZE, resp.body().size()));
         resp.body().release();
       } else {
         outstandingRpcs.remove(resp.requestId);
@@ -208,9 +208,9 @@ public void handle(ResponseMessage message) throws Exception {
       BaseResponseCallback listener = outstandingRpcs.get(resp.requestId);
       if (listener == null) {
         logger.warn("Ignoring response for RPC {} from {} ({}) since it is not outstanding",
-          MDC.of(LogKeys.REQUEST_ID$.MODULE$, resp.requestId),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)),
-          MDC.of(LogKeys.ERROR$.MODULE$, resp.errorString));
+          MDC.of(LogKeys.REQUEST_ID, resp.requestId),
+          MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)),
+          MDC.of(LogKeys.ERROR, resp.errorString));
       } else {
         outstandingRpcs.remove(resp.requestId);
         listener.onFailure(new RuntimeException(resp.errorString));
@@ -222,9 +222,9 @@ public void handle(ResponseMessage message) throws Exception {
         if (listener == null) {
           logger.warn("Ignoring response for MergedBlockMetaRequest {} from {} ({} bytes) since "
             + "it is not outstanding",
-            MDC.of(LogKeys.REQUEST_ID$.MODULE$, resp.requestId),
-            MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)),
-            MDC.of(LogKeys.RESPONSE_BODY_SIZE$.MODULE$, resp.body().size()));
+            MDC.of(LogKeys.REQUEST_ID, resp.requestId),
+            MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)),
+            MDC.of(LogKeys.RESPONSE_BODY_SIZE, resp.body().size()));
         } else {
           outstandingRpcs.remove(resp.requestId);
           listener.onSuccess(resp.getNumChunks(), resp.body());
@@ -269,7 +269,7 @@ public void handle(ResponseMessage message) throws Exception {
         }
       } else {
         logger.warn("Stream failure with unknown callback: {}",
-          MDC.of(LogKeys.ERROR$.MODULE$, resp.error));
+          MDC.of(LogKeys.ERROR, resp.error));
       }
     } else {
       throw new IllegalStateException("Unknown response type: " + message.type());

common/network-common/src/main/java/org/apache/spark/network/crypto/AuthRpcHandler.java

@@ -93,7 +93,7 @@ protected boolean doAuthChallenge(
     } catch (RuntimeException e) {
       if (conf.saslFallback()) {
         LOG.warn("Failed to parse new auth challenge, reverting to SASL for client {}.",
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, channel.remoteAddress()));
+          MDC.of(LogKeys.HOST_PORT, channel.remoteAddress()));
         saslHandler = new SaslRpcHandler(conf, channel, null, secretKeyHolder);
         message.position(position);
         message.limit(limit);

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

@@ -66,8 +66,8 @@ public void encode(ChannelHandlerContext ctx, Message in, List<Object> out) thro
           // Re-encode this message as a failure response.
           String error = e.getMessage() != null ? e.getMessage() : "null";
           logger.error("Error processing {} for client {}", e,
-            MDC.of(LogKeys.MESSAGE$.MODULE$, in),
-            MDC.of(LogKeys.HOST_PORT$.MODULE$, ctx.channel().remoteAddress()));
+            MDC.of(LogKeys.MESSAGE, in),
+            MDC.of(LogKeys.HOST_PORT, ctx.channel().remoteAddress()));
           encode(ctx, resp.createFailureResponse(error), out);
         } else {
           throw e;

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

@@ -71,8 +71,8 @@ public void encode(ChannelHandlerContext ctx, Message in, List<Object> out) thro
           // Re-encode this message as a failure response.
           String error = e.getMessage() != null ? e.getMessage() : "null";
           logger.error("Error processing {} for client {}", e,
-            MDC.of(LogKeys.MESSAGE$.MODULE$, in),
-            MDC.of(LogKeys.HOST_PORT$.MODULE$, ctx.channel().remoteAddress()));
+            MDC.of(LogKeys.MESSAGE, in),
+            MDC.of(LogKeys.HOST_PORT, ctx.channel().remoteAddress()));
           encode(ctx, resp.createFailureResponse(error), out);
         } else {
           throw e;

common/network-common/src/main/java/org/apache/spark/network/server/ChunkFetchRequestHandler.java

@@ -74,7 +74,7 @@ public ChunkFetchRequestHandler(
   @Override
   public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
     logger.warn("Exception in connection from {}", cause,
-      MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(ctx.channel())));
+      MDC.of(LogKeys.HOST_PORT, getRemoteAddress(ctx.channel())));
     ctx.close();
   }
 
@@ -96,8 +96,8 @@ public void processFetchRequest(
       long chunksBeingTransferred = streamManager.chunksBeingTransferred();
       if (chunksBeingTransferred >= maxChunksBeingTransferred) {
         logger.warn("The number of chunks being transferred {} is above {}, close the connection.",
-          MDC.of(LogKeys.NUM_CHUNKS$.MODULE$, chunksBeingTransferred),
-          MDC.of(LogKeys.MAX_NUM_CHUNKS$.MODULE$, maxChunksBeingTransferred));
+          MDC.of(LogKeys.NUM_CHUNKS, chunksBeingTransferred),
+          MDC.of(LogKeys.MAX_NUM_CHUNKS, maxChunksBeingTransferred));
         channel.close();
         return;
       }
@@ -111,8 +111,8 @@ public void processFetchRequest(
       }
     } catch (Exception e) {
       logger.error("Error opening block {} for request from {}", e,
-        MDC.of(LogKeys.STREAM_CHUNK_ID$.MODULE$, msg.streamChunkId),
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+        MDC.of(LogKeys.STREAM_CHUNK_ID, msg.streamChunkId),
+        MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
       respond(channel, new ChunkFetchFailure(msg.streamChunkId,
         Throwables.getStackTraceAsString(e)));
       return;
@@ -153,8 +153,8 @@ private ChannelFuture respond(
       } else {
         logger.error("Error sending result {} to {}; closing connection",
           future.cause(),
-          MDC.of(LogKeys.RESULT$.MODULE$, result),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, remoteAddress));
+          MDC.of(LogKeys.RESULT, result),
+          MDC.of(LogKeys.HOST_PORT, remoteAddress));
         channel.close();
       }
     });

common/network-common/src/main/java/org/apache/spark/network/server/TransportChannelHandler.java

@@ -88,7 +88,7 @@ public TransportClient getClient() {
   @Override
   public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
     logger.warn("Exception in connection from {}", cause,
-      MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(ctx.channel())));
+      MDC.of(LogKeys.HOST_PORT, getRemoteAddress(ctx.channel())));
     requestHandler.exceptionCaught(cause);
     responseHandler.exceptionCaught(cause);
     ctx.close();
@@ -168,9 +168,9 @@ public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exc
             logger.error("Connection to {} has been quiet for {} ms while there are outstanding " +
               "requests. Assuming connection is dead; please adjust" +
               " spark.{}.io.connectionTimeout if this is wrong.",
-              MDC.of(LogKeys.HOST_PORT$.MODULE$, address),
-              MDC.of(LogKeys.TIMEOUT$.MODULE$, requestTimeoutNs / 1000 / 1000),
-              MDC.of(LogKeys.MODULE_NAME$.MODULE$, transportContext.getConf().getModuleName()));
+              MDC.of(LogKeys.HOST_PORT, address),
+              MDC.of(LogKeys.TIMEOUT, requestTimeoutNs / 1000 / 1000),
+              MDC.of(LogKeys.MODULE_NAME, transportContext.getConf().getModuleName()));
             client.timeOut();
             ctx.close();
           } else if (closeIdleConnections) {

common/network-common/src/main/java/org/apache/spark/network/server/TransportRequestHandler.java

@@ -132,8 +132,8 @@ private void processStreamRequest(final StreamRequest req) {
       long chunksBeingTransferred = streamManager.chunksBeingTransferred();
       if (chunksBeingTransferred >= maxChunksBeingTransferred) {
         logger.warn("The number of chunks being transferred {} is above {}, close the connection.",
-          MDC.of(LogKeys.NUM_CHUNKS$.MODULE$, chunksBeingTransferred),
-          MDC.of(LogKeys.MAX_NUM_CHUNKS$.MODULE$, maxChunksBeingTransferred));
+          MDC.of(LogKeys.NUM_CHUNKS, chunksBeingTransferred),
+          MDC.of(LogKeys.MAX_NUM_CHUNKS, maxChunksBeingTransferred));
         channel.close();
         return;
       }
@@ -143,8 +143,8 @@ private void processStreamRequest(final StreamRequest req) {
       buf = streamManager.openStream(req.streamId);
     } catch (Exception e) {
       logger.error("Error opening stream {} for request from {}", e,
-        MDC.of(LogKeys.STREAM_ID$.MODULE$, req.streamId),
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+        MDC.of(LogKeys.STREAM_ID, req.streamId),
+        MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
       respond(new StreamFailure(req.streamId, Throwables.getStackTraceAsString(e)));
       return;
     }
@@ -177,8 +177,8 @@ public void onFailure(Throwable e) {
       });
     } catch (Exception e) {
       logger.error("Error while invoking RpcHandler#receive() on RPC id {} from {}", e,
-        MDC.of(LogKeys.REQUEST_ID$.MODULE$, req.requestId),
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+        MDC.of(LogKeys.REQUEST_ID, req.requestId),
+        MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
       respond(new RpcFailure(req.requestId, Throwables.getStackTraceAsString(e)));
     } finally {
       req.body().release();
@@ -264,8 +264,8 @@ public String getID() {
           new NioManagedBuffer(blockPushNonFatalFailure.getResponse())));
       } else {
         logger.error("Error while invoking RpcHandler#receive() on RPC id {} from {}", e,
-          MDC.of(LogKeys.REQUEST_ID$.MODULE$, req.requestId),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+          MDC.of(LogKeys.REQUEST_ID, req.requestId),
+          MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
         respond(new RpcFailure(req.requestId, Throwables.getStackTraceAsString(e)));
       }
       // We choose to totally fail the channel, rather than trying to recover as we do in other
@@ -282,7 +282,7 @@ private void processOneWayMessage(OneWayMessage req) {
       rpcHandler.receive(reverseClient, req.body().nioByteBuffer());
     } catch (Exception e) {
       logger.error("Error while invoking RpcHandler#receive() for one-way message from {}.", e,
-        MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+        MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
     } finally {
       req.body().release();
     }
@@ -307,10 +307,10 @@ public void onFailure(Throwable e) {
       });
     } catch (Exception e) {
       logger.error("Error while invoking receiveMergeBlockMetaReq() for appId {} shuffleId {} "
-        + "reduceId {} from {}", e, MDC.of(LogKeys.APP_ID$.MODULE$, req.appId),
-          MDC.of(LogKeys.SHUFFLE_ID$.MODULE$, req.shuffleId),
-          MDC.of(LogKeys.REDUCE_ID$.MODULE$, req.reduceId),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, getRemoteAddress(channel)));
+        + "reduceId {} from {}", e, MDC.of(LogKeys.APP_ID, req.appId),
+          MDC.of(LogKeys.SHUFFLE_ID, req.shuffleId),
+          MDC.of(LogKeys.REDUCE_ID, req.reduceId),
+          MDC.of(LogKeys.HOST_PORT, getRemoteAddress(channel)));
       respond(new RpcFailure(req.requestId, Throwables.getStackTraceAsString(e)));
     }
   }
@@ -326,8 +326,8 @@ private ChannelFuture respond(Encodable result) {
         logger.trace("Sent result {} to client {}", result, remoteAddress);
       } else {
         logger.error("Error sending result {} to {}; closing connection", future.cause(),
-          MDC.of(LogKeys.RESULT$.MODULE$, result),
-          MDC.of(LogKeys.HOST_PORT$.MODULE$, remoteAddress));
+          MDC.of(LogKeys.RESULT, result),
+          MDC.of(LogKeys.HOST_PORT, remoteAddress));
         channel.close();
       }
     });

common/network-common/src/main/java/org/apache/spark/network/util/LevelDBProvider.java

@@ -50,7 +50,7 @@ public static DB initLevelDB(File dbFile, StoreVersion version, ObjectMapper map
         tmpDb = JniDBFactory.factory.open(dbFile, options);
       } catch (NativeDB.DBException e) {
         if (e.isNotFound() || e.getMessage().contains(" does not exist ")) {
-          logger.info("Creating state database at {}", MDC.of(LogKeys.PATH$.MODULE$, dbFile));
+          logger.info("Creating state database at {}", MDC.of(LogKeys.PATH, dbFile));
           options.createIfMissing(true);
           try {
             tmpDb = JniDBFactory.factory.open(dbFile, options);
@@ -61,16 +61,16 @@ public static DB initLevelDB(File dbFile, StoreVersion version, ObjectMapper map
           // the leveldb file seems to be corrupt somehow.  Lets just blow it away and create a new
           // one, so we can keep processing new apps
           logger.error("error opening leveldb file {}. Creating new file, will not be able to " +
-              "recover state for existing applications", e, MDC.of(LogKeys.PATH$.MODULE$, dbFile));
+              "recover state for existing applications", e, MDC.of(LogKeys.PATH, dbFile));
           if (dbFile.isDirectory()) {
             for (File f : dbFile.listFiles()) {
               if (!f.delete()) {
-                logger.warn("error deleting {}", MDC.of(LogKeys.PATH$.MODULE$, f.getPath()));
+                logger.warn("error deleting {}", MDC.of(LogKeys.PATH, f.getPath()));
               }
             }
           }
           if (!dbFile.delete()) {
-            logger.warn("error deleting {}", MDC.of(LogKeys.PATH$.MODULE$, dbFile.getPath()));
+            logger.warn("error deleting {}", MDC.of(LogKeys.PATH, dbFile.getPath()));
           }
           options.createIfMissing(true);
           try {