fix

Author: yuzelin

paimon-flink/paimon-flink-common/src/main/java/org/apache/paimon/flink/lookup/FullCacheLookupTable.java

@@ -55,6 +55,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
@@ -92,7 +93,7 @@ public abstract class FullCacheLookupTable implements LookupTable {
     private final FileStoreTable table;
     private Future<?> refreshFuture;
     private LookupStreamingReader reader;
-    private List<BinaryRow> scanPartitions;
+    private List<BinaryRow> scanPartitions = Collections.emptyList();
     @Nullable private Predicate partitionFilter;
     @Nullable private Filter<InternalRow> cacheRowFilter;