Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/4358#discussion_r142126300
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/blob/AbstractBlobCache.java
---
@@ -0,0 +1,241 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.runtime.blob;
+
+import org.apache.flink.api.common.JobID;
+import org.apache.flink.configuration.BlobServerOptions;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.util.FileUtils;
+
+import org.slf4j.Logger;
+
+import javax.annotation.Nullable;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static org.apache.flink.util.Preconditions.checkArgument;
+import static org.apache.flink.util.Preconditions.checkNotNull;
+
+/**
+ * Abstract base class for permanent and transient BLOB files.
+ */
+public abstract class AbstractBlobCache implements Closeable {
+
+ /**
+ * The log object used for debugging.
+ */
+ protected final Logger LOG;
--- End diff --
I think only static variables should be written in capital letters.
---
