diff --git a/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/BaseFlightReader.java b/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/BaseFlightReader.java
index b30f561fda..f974cdfa6e 100644
--- a/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/BaseFlightReader.java
+++ b/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/BaseFlightReader.java
@@ -37,7 +37,7 @@
 import org.apache.arrow.vector.ipc.ArrowReader;
 import org.apache.arrow.vector.ipc.message.ArrowRecordBatch;
 import org.apache.arrow.vector.types.pojo.Schema;
-import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /** Base class for ArrowReaders based on consuming data from FlightEndpoints. */
 public abstract class BaseFlightReader extends ArrowReader {
@@ -45,8 +45,8 @@ public abstract class BaseFlightReader extends ArrowReader {
   private final List<FlightEndpoint> flightEndpoints;
   private final Supplier<List<FlightEndpoint>> rpcCall;
   private int nextEndpointIndex = 0;
-  private @MonotonicNonNull FlightStream currentStream = null;
-  private @MonotonicNonNull Schema schema = null;
+  private @Nullable FlightStream currentStream = null;
+  private @Nullable Schema schema = null;
   private long bytesRead = 0;
   protected final FlightSqlClientWithCallOptions client;
   protected final LoadingCache<Location, FlightSqlClientWithCallOptions> clientCache;
@@ -65,7 +65,7 @@ protected BaseFlightReader(
 
   @Override
   public boolean loadNextBatch() throws IOException {
-    Preconditions.checkNotNull(currentStream);
+    Preconditions.checkState(currentStream != null);
     if (!currentStream.next()) {
       if (nextEndpointIndex >= flightEndpoints.size()) {
         return false;
@@ -94,7 +94,7 @@ public boolean loadNextBatch() throws IOException {
 
   @Override
   protected Schema readSchema() throws IOException {
-    Preconditions.checkNotNull(currentStream);
+    Preconditions.checkState(schema != null);
     return schema;
   }
 
diff --git a/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/GetInfoMetadataReader.java b/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/GetInfoMetadataReader.java
index 16581080ae..3dffc1268e 100644
--- a/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/GetInfoMetadataReader.java
+++ b/java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/GetInfoMetadataReader.java
@@ -40,7 +40,6 @@
 import org.apache.arrow.vector.VectorSchemaRoot;
 import org.apache.arrow.vector.complex.DenseUnionVector;
 import org.apache.arrow.vector.types.pojo.Schema;
-import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /** Helper class to track state needed to build up the info structure. */
@@ -51,12 +50,12 @@ final class GetInfoMetadataReader extends BaseFlightReader {
 
   private final BufferAllocator allocator;
   private final Collection<Integer> requestedCodes;
-  private @MonotonicNonNull UInt4Vector infoCodes = null;
-  private @MonotonicNonNull DenseUnionVector infoValues = null;
-  private @MonotonicNonNull VarCharVector stringValues = null;
+  private @Nullable UInt4Vector infoCodes = null;
+  private @Nullable DenseUnionVector infoValues = null;
+  private @Nullable VarCharVector stringValues = null;
   private boolean hasInMemoryDataBeenWritten = false;
-  private boolean hasInMemoryData;
-  private boolean hasSupportedCodes;
+  private final boolean hasInMemoryData;
+  private final boolean hasSupportedCodes;
   private boolean hasRequestBeenIssued = false;
 
   @FunctionalInterface
@@ -75,14 +74,14 @@ void accept(
     SUPPORTED_CODES.put(
         FlightSql.SqlInfo.FLIGHT_SQL_SERVER_NAME.getNumber(),
         (b, sqlInfo, srcIndex, dstIndex) -> {
-          Preconditions.checkNotNull(b.infoCodes);
+          Preconditions.checkState(b.infoCodes != null);
           b.infoCodes.setSafe(dstIndex, AdbcInfoCode.VENDOR_NAME.getValue());
           b.setStringValue(dstIndex, sqlInfo.getVarCharVector(STRING_VALUE_TYPE_ID).get(srcIndex));
         });
     SUPPORTED_CODES.put(
         FlightSql.SqlInfo.FLIGHT_SQL_SERVER_VERSION.getNumber(),
         (b, sqlInfo, srcIndex, dstIndex) -> {
-          Preconditions.checkNotNull(b.infoCodes);
+          Preconditions.checkState(b.infoCodes != null);
           b.infoCodes.setSafe(dstIndex, AdbcInfoCode.VENDOR_VERSION.getValue());
           b.setStringValue(dstIndex, sqlInfo.getVarCharVector(STRING_VALUE_TYPE_ID).get(srcIndex));
         });
@@ -120,16 +119,18 @@ static GetInfoMetadataReader CreateGetInfoMetadataReader(
     this.hasInMemoryData =
         requestedCodes.contains(AdbcInfoCode.DRIVER_NAME.getValue())
             || requestedCodes.contains(AdbcInfoCode.DRIVER_VERSION.getValue());
+    boolean hasRequestedCode = false;
     for (Integer requestedCode : requestedCodes) {
       if (SUPPORTED_CODES.containsKey(requestedCode)) {
-        hasSupportedCodes = true;
+        hasRequestedCode = true;
         break;
       }
     }
+    hasSupportedCodes = hasRequestedCode;
   }
 
   void setStringValue(int index, byte[] value) {
-    Preconditions.checkNotNull(infoValues, stringValues);
+    Preconditions.checkState(infoValues != null && stringValues != null);
     infoValues.setValueCount(index + 1);
     infoValues.setTypeId(index, STRING_VALUE_TYPE_ID);
     stringValues.setSafe(index, value);