Add license headers

Author: mike-evolved

java/src/main/java/org/rocksdb/AdvancedCacheOptions.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 /**

java/src/main/java/org/rocksdb/CacheTier.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+// COPYING file in the root directory) and Apache 2.0 License
+// (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 /**

java/src/main/java/org/rocksdb/FileTemperatureAge.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+// COPYING file in the root directory) and Apache 2.0 License
+// (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 /**

java/src/main/java/org/rocksdb/MemoryAllocator.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 /**

java/src/main/java/org/rocksdb/RibbonFilter.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 import java.util.Objects;

java/src/main/java/org/rocksdb/SecondaryCache.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 /**

java/src/main/java/org/rocksdb/Temperature.java

@@ -1,3 +1,8 @@
+// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
 package org.rocksdb;
 
 /**