Fix native ReadOptions leak in RocksDB.close() (Java)

java/src/main/java/org/rocksdb/RocksDB.java

@@ -43,6 +43,13 @@ private enum LibraryState {
 
   final List<ColumnFamilyHandle> ownedColumnFamilyHandles = new ArrayList<>();
 
+  /**
+   * Package-private accessor for {@link #defaultReadOptions_}, for testing only.
+   */
+  ReadOptions getDefaultReadOptions() {
+    return defaultReadOptions_;
+  }
+
   /**
    * Loads the necessary library files.
    * Calling this method twice will have no effect.
@@ -696,6 +703,7 @@ public void close() {
       } catch (final RocksDBException e) {
         // silently ignore the error report
       } finally {
+        defaultReadOptions_.close();
         disposeInternal();
       }
     }

java/src/test/java/org/rocksdb/RocksDBTest.java

@@ -178,6 +178,17 @@ public void createColumnFamiliesfromDescriptors() throws RocksDBException {
     }
   }
 
+  @Test
+  public void closeReleasesDefaultReadOptions() throws RocksDBException {
+    try (final Options options = new Options().setCreateIfMissing(true)) {
+      final RocksDB db = RocksDB.open(options, dbFolder.getRoot().getAbsolutePath());
+      final ReadOptions defaultReadOptions = db.getDefaultReadOptions();
+      assertThat(defaultReadOptions.isOwningHandle()).isTrue();
+      db.close();
+      assertThat(defaultReadOptions.isOwningHandle()).isFalse();
+    }
+  }
+
   @Test
   public void put() throws RocksDBException {
     try (final RocksDB db = RocksDB.open(dbFolder.getRoot().getAbsolutePath());

unreleased_history/bug_fixes/java_close_readoptions_leak.md

@@ -0,0 +1 @@
+Fixed a native memory leak in the Java API where `RocksDB.close()` did not release the default `ReadOptions`, leaking one native object per opened DB instance.