Addressing review comments.

clients/unshaded/src/main/java/tachyon/client/file/AbstractTachyonFileSystem.java

@@ -163,12 +163,6 @@ public List<FileInfo> listStatus(TachyonFile file, ListStatusOptions options) th
     }
   }
 
-  /**
-   * {@inheritDoc}
-   *
-   * To add the data into Tachyon space perform an operation with the cache option specified, for
-   * example the load command of the Tachyon Shell.
-   */
   @Override
   public long loadMetadata(TachyonURI path, LoadMetadataOptions options)
       throws IOException, TachyonException {

clients/unshaded/src/main/java/tachyon/client/file/FileInStream.java

@@ -180,7 +180,7 @@ public void seek(long pos) throws IOException {
       return;
     }
     Preconditions.checkArgument(pos >= 0, "Seek position is negative: " + pos);
-    Preconditions.checkArgument(pos <= mFileLength, "Seek position is past EOF: " + pos
+    Preconditions.checkArgument(pos < mFileLength, "Seek position is past EOF: " + pos
         + ", fileSize = " + mFileLength);
 
     seekBlockInStream(pos);

clients/unshaded/src/main/java/tachyon/client/file/FileOutStream.java

@@ -60,7 +60,6 @@ public final class FileOutStream extends OutputStream implements Cancelable {
   private final UnderStorageType mUnderStorageType;
   private final FileSystemContext mContext;
   private final OutputStream mUnderStorageOutputStream;
-  private final WorkerClient mWorkerClient;
   private final long mNonce;
 
   private boolean mCanceled;
@@ -97,9 +96,7 @@ public FileOutStream(long fileId, OutStreamOptions options) throws IOException {
         }
       }
       mUnderStorageOutputStream = ufs.create(fileName, (int) mBlockSize);
-      mWorkerClient = BlockStoreContext.INSTANCE.acquireWorkerClient();
     } else {
-      mWorkerClient = null;
       mUnderStorageOutputStream = null;
     }
     mClosed = false;
@@ -136,11 +133,12 @@ public void close() throws IOException {
       } else {
         mUnderStorageOutputStream.flush();
         mUnderStorageOutputStream.close();
+        WorkerClient workerClient = BlockStoreContext.INSTANCE.acquireWorkerClient();
         try {
           // TODO(yupeng): Investigate if this RPC can be moved to master.
-          mWorkerClient.addCheckpoint(mFileId, mNonce);
+          workerClient.addCheckpoint(mFileId, mNonce);
         } finally {
-          BlockStoreContext.INSTANCE.releaseWorkerClient(mWorkerClient);
+          BlockStoreContext.INSTANCE.releaseWorkerClient(workerClient);
         }
         canComplete = true;
       }

clients/unshaded/src/main/java/tachyon/client/file/TachyonFileSystemCore.java

@@ -100,7 +100,7 @@ List<FileInfo> listStatus(TachyonFile file, ListStatusOptions options) throws IO
   /**
    * Loads metadata about a file in UFS to Tachyon. No data will be transferred.
    *
-   * @param path the path to create the file in Tachyon
+   * @param path the path for which to load metadat from UFS
    * @param options method options
    * @return the file id of the resulting file in Tachyon
    * @throws IOException if a non-Tachyon exception occurs

common/src/main/java/tachyon/client/WorkerFileSystemMasterClient.java

@@ -66,19 +66,19 @@ protected void afterConnect() {
   }
 
   /**
-   * Adds a checkpoint.
+   * Persists a file.
    *
    * @param fileId the file id
    * @param length the checkpoint length
    * @return whether operation succeeded or not
    * @throws IOException if an I/O error occurs
    */
-  public synchronized boolean addCheckpoint(long fileId, long length) throws IOException {
+  public synchronized boolean persistFile(long fileId, long length) throws IOException {
     int retry = 0;
     while (!mClosed && (retry ++) <= RPC_MAX_NUM_RETRY) {
       connect();
       try {
-        return mClient.addCheckpoint(fileId, length);
+        return mClient.persistFile(fileId, length);
       } catch (FileDoesNotExistException e) {
         throw new IOException(e);
       } catch (TException e) {