fix checkstyle

Author: hnwyllmm

c/src/test/java/org/apache/arrow/c/ExceptionTest.java

@@ -27,16 +27,12 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Collectors;
-import org.apache.arrow.c.jni.CDataJniException;
 import org.apache.arrow.memory.BufferAllocator;
 import org.apache.arrow.memory.RootAllocator;
-import org.apache.arrow.vector.IntVector;
 import org.apache.arrow.vector.VectorLoader;
 import org.apache.arrow.vector.VectorSchemaRoot;
-import org.apache.arrow.vector.VectorUnloader;
 import org.apache.arrow.vector.dictionary.Dictionary;
 import org.apache.arrow.vector.dictionary.DictionaryProvider;
 import org.apache.arrow.vector.ipc.ArrowReader;