Java-API: byteCompressionType should be declared as primitive type byte (#7981)

Summary:
The variable `byteCompressionType` is only assigned values of primitive type and is never 'null', but it is declared with the boxed type 'Byte'.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7981

Reviewed By: ajkr

Differential Revision: D26546600

Pulled By: jay-zhuang

fbshipit-source-id: 07b579cdfcfc2262a448ca3626e216416fd05892

java/src/main/java/org/rocksdb/ColumnFamilyOptions.java

@@ -339,7 +339,7 @@ public class ColumnFamilyOptions extends RocksObject
     final byte[] byteCompressionTypes =
         compressionPerLevel(nativeHandle_);
     final List<CompressionType> compressionLevels = new ArrayList<>();
-    for (final Byte byteCompressionType : byteCompressionTypes) {
+    for (final byte byteCompressionType : byteCompressionTypes) {
       compressionLevels.add(CompressionType.getCompressionType(
           byteCompressionType));
     }

java/src/main/java/org/rocksdb/Options.java

@@ -1408,7 +1408,7 @@ public class Options extends RocksObject
     final byte[] byteCompressionTypes =
         compressionPerLevel(nativeHandle_);
     final List<CompressionType> compressionLevels = new ArrayList<>();
-    for (final Byte byteCompressionType : byteCompressionTypes) {
+    for (final byte byteCompressionType : byteCompressionTypes) {
       compressionLevels.add(CompressionType.getCompressionType(
           byteCompressionType));
     }