A bit more test of Java API on closed iterators

java/src/test/java/org/rocksdb/IteratorClosedDBTest.java

@@ -46,12 +46,21 @@ public void shouldNotCrashJavaRocks() throws RocksDBException {
       it.seekToFirst();
       assertThat(it.isValid()).isTrue();
 
+      byte[] valueOK = it.value();
+      assertThat(valueOK).isEqualTo(value);
+
       // Close should work because iterator references are now cleaned up
       // Previously would have thrown an exception here (assertion failure in C++) -
       // when built with DEBUG_LEVEL=1
       // Because the outstanding iterator has a reference to the column family which is being closed
       db.close();
 
+      try {
+        byte[] valueShouldAssert = it.value();
+        throw new RuntimeException("it.value() should cause an assertion");
+      } catch (AssertionError ignored) {
+      }
+
       // should assert
       try {
         boolean isValidShouldAssert = it.isValid();