Revert HADOOP-9692.

This reverts commit 381610da620121c02073dbbaac669b80b41959b4.
This reverts commit b5ca649bff01c906033d71c9f983b4cdaa71a9d1.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -902,9 +902,6 @@ Release 2.8.0 - UNRELEASED
 
     HADOOP-10406. TestIPC.testIpcWithReaderQueuing may fail. (Xiao Chen via wang)
 
-    HADOOP-9692. Improving log message when SequenceFile reader throws
-    EOFException on zero-length file. Contributed by Zhe Zhang and Chu Tong.
-
   OPTIMIZATIONS
 
     HADOOP-11785. Reduce the number of listStatus operation in distcp

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/SequenceFile.java

@@ -1912,26 +1912,17 @@ public class SequenceFile {
      */
     private void init(boolean tempReader) throws IOException {
       byte[] versionBlock = new byte[VERSION.length];
-      String exceptionMsg = this + " not a SequenceFile";
-
-      // Try to read sequence file header.
-      try {
-        in.readFully(versionBlock);
-      } catch (EOFException e) {
-        throw new EOFException(exceptionMsg);
-      }
+      in.readFully(versionBlock);
 
       if ((versionBlock[0] != VERSION[0]) ||
           (versionBlock[1] != VERSION[1]) ||
-          (versionBlock[2] != VERSION[2])) {
+          (versionBlock[2] != VERSION[2]))
         throw new IOException(this + " not a SequenceFile");
-      }
 
       // Set 'version'
       version = versionBlock[3];
-      if (version > VERSION[3]) {
+      if (version > VERSION[3])
         throw new VersionMismatchException(VERSION[3], version);
-      }
 
       if (version < BLOCK_COMPRESS_VERSION) {
         UTF8 className = new UTF8();

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/TestSequenceFile.java

@@ -522,27 +522,6 @@ public class TestSequenceFile extends TestCase {
     assertTrue("InputStream for " + path + " should have been closed.", openedFile[0].isClosed());
   }
 
-  /**
-   * Test to makes sure zero length sequence file is handled properly while
-   * initializing.
-   */
-  public void testInitZeroLengthSequenceFile() throws IOException {
-    Configuration conf = new Configuration();
-    LocalFileSystem fs = FileSystem.getLocal(conf);
-
-    // create an empty file (which is not a valid sequence file)
-    Path path = new Path(System.getProperty("test.build.data", ".") +
-      "/zerolength.seq");
-    fs.create(path).close();
-
-    try {
-      new SequenceFile.Reader(conf, SequenceFile.Reader.file(path));
-      fail("IOException expected.");
-    } catch (IOException expected) {
-      assertTrue(expected instanceof EOFException);
-    }
-  }
-
    /**
    * Test that makes sure createWriter succeeds on a file that was 
    * already created