HADOOP-19932. Prune obsolete classes in org.apache.hadoop.io.serializer

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

@@ -22,15 +22,13 @@
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
-import org.apache.hadoop.io.serializer.DeserializerComparator;
 
 /**
  * <p>
  * A {@link Comparator} that operates directly on byte representations of
  * objects.
  * </p>
  * @param <T> generic type.
- * @see DeserializerComparator
  */
 @InterfaceAudience.Public
 @InterfaceStability.Stable

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/file/tfile/TFile.java

@@ -48,7 +48,6 @@
 import org.apache.hadoop.io.file.tfile.CompareUtils.BytesComparator;
 import org.apache.hadoop.io.file.tfile.CompareUtils.MemcmpRawComparator;
 import org.apache.hadoop.io.file.tfile.Utils.Version;
-import org.apache.hadoop.io.serializer.JavaSerializationComparator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -268,8 +267,7 @@ private enum State {
      *          Currently, we only support RawComparators that can be
      *          constructed through the default constructor (with no
      *          parameters). Parameterized RawComparators such as
-     *          {@link WritableComparator} or
-     *          {@link JavaSerializationComparator} may not be directly used.
+     *          {@link WritableComparator} may not be directly used.
      *          One should write a wrapper class that inherits from such classes
      *          and use its default constructor to perform proper
      *          initialization.

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/shell/TestTextCommand.java

@@ -35,6 +35,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.io.SequenceFile;
+import org.apache.hadoop.io.Text;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
@@ -513,22 +514,20 @@ private static byte[] generateEmptyAvroBinaryData() {
 
   private static void createEmptySequenceFile(String fileName, Configuration conf)
       throws IOException {
-    conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization");
     Path path = new Path(fileName);
     SequenceFile.Writer writer = SequenceFile.createWriter(conf, SequenceFile.Writer.file(path),
-        SequenceFile.Writer.keyClass(String.class), SequenceFile.Writer.valueClass(String.class));
+        SequenceFile.Writer.keyClass(Text.class), SequenceFile.Writer.valueClass(Text.class));
     writer.close();
   }
 
   private static void createNonWritableSequenceFile(String fileName, Configuration conf)
       throws IOException {
-    conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization");
     Path path = new Path(fileName);
     try (SequenceFile.Writer writer = SequenceFile.createWriter(conf,
-        SequenceFile.Writer.file(path), SequenceFile.Writer.keyClass(String.class),
-        SequenceFile.Writer.valueClass(String.class))) {
-      writer.append("Key1", "Value1");
-      writer.append("Key2", "Value2");
+        SequenceFile.Writer.file(path), SequenceFile.Writer.keyClass(Text.class),
+        SequenceFile.Writer.valueClass(Text.class))) {
+      writer.append(new Text("Key1"), new Text("Value1"));
+      writer.append(new Text("Key2"), new Text("Value2"));
     }
   }