Switch json-io stream deser to JsonIo.toMaps() (toObjects deprecated)

JsonIo.toObjects(InputStream, ReadOptions, Class) is deprecated as of
json-io 4.101.0+ (will be removed in 5.0.0). The clean substitute is
JsonIo.toMaps(InputStream).asClass(JsonObject.class), which routes
through the same MapResolver path and manages Maps-mode options
internally via its own cache (no need to pass options).

The result is materialized as JsonObject so the round-trip verification
in JsonBenchmark.test() recognizes it (instanceof JsonObject branch
re-serializes via WriteOptionsBuilder().standardJson().build() before
parity-checking against Jackson's Users/Clients POJOs).

Removed the now-unused jsonioReadOptionsMaps() method (and its cached
field) from JsonProvider, UsersJsonProvider, and ClientsJsonProvider --
the provider is the harness's "cache library config once" pattern, and
toMaps() handles its own caching.

Files:
- stream/Deserialization.java: switch to JsonIo.toMaps().asClass(JsonObject.class)
- provider/JsonProvider.java: drop jsonioReadOptionsMaps() declaration
- provider/UsersJsonProvider.java: drop the field + override
- provider/ClientsJsonProvider.java: drop the field + override

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 2 people

src/main/java/com/github/fabienrenaud/jjb/provider/ClientsJsonProvider.java

@@ -1,7 +1,5 @@
 package com.github.fabienrenaud.jjb.provider;
 
-import com.cedarsoftware.io.ReadOptions;
-import com.cedarsoftware.io.ReadOptionsBuilder;
 import com.cedarsoftware.io.WriteOptions;
 import com.cedarsoftware.io.WriteOptionsBuilder;
 import com.dslplatform.json.DslJson;
@@ -166,10 +164,10 @@ public void toJson(com.squareup.moshi.JsonWriter writer, @Nullable OffsetDateTim
 
     private final com.bigcloud.djomo.Json djomo = new com.bigcloud.djomo.Json();
 
-    // json-io options are immutable+thread-safe once built; cache one instance per provider
-    // to match how every other library here caches its mapper/parser/serializer.
+    // json-io WriteOptions is immutable+thread-safe once built; cache one instance per provider
+    // to match how every other library here caches its mapper/parser/serializer. Read-side uses
+    // JsonIo.toMaps()/toJava() which manage their own option caches internally.
     private final WriteOptions jsonioWriteOptions = new WriteOptionsBuilder().standardJson().build();
-    private final ReadOptions jsonioReadOptionsMaps = new ReadOptionsBuilder().returnAsNativeJsonObjects().build();
 
     public ClientsJsonProvider() {
 
@@ -305,11 +303,6 @@ public WriteOptions jsonioWriteOptions() {
         return jsonioWriteOptions;
     }
 
-    @Override
-    public ReadOptions jsonioReadOptionsMaps() {
-        return jsonioReadOptionsMaps;
-    }
-
     private static final ThreadLocal<QuickbufSchema.Clients> QUICKBUF_MESSAGE = ThreadLocal.withInitial(QuickbufSchema.Clients::newInstance);
     private static final ThreadLocal<JsonSink> QUICKBUF_SINK = ThreadLocal.withInitial(() -> JsonSink.newInstance()
             .setPrettyPrinting(false)

src/main/java/com/github/fabienrenaud/jjb/provider/JsonProvider.java

@@ -1,6 +1,5 @@
 package com.github.fabienrenaud.jjb.provider;
 
-import com.cedarsoftware.io.ReadOptions;
 import com.cedarsoftware.io.WriteOptions;
 import com.dslplatform.json.DslJson;
 import com.fasterxml.jackson.core.JsonFactory;
@@ -66,6 +65,4 @@ public interface JsonProvider<T> {
 
     WriteOptions jsonioWriteOptions();
 
-    ReadOptions jsonioReadOptionsMaps();
-
 }

src/main/java/com/github/fabienrenaud/jjb/provider/UsersJsonProvider.java

@@ -1,7 +1,5 @@
 package com.github.fabienrenaud.jjb.provider;
 
-import com.cedarsoftware.io.ReadOptions;
-import com.cedarsoftware.io.ReadOptionsBuilder;
 import com.cedarsoftware.io.WriteOptions;
 import com.cedarsoftware.io.WriteOptionsBuilder;
 import com.dslplatform.json.DslJson;
@@ -62,10 +60,10 @@ public class UsersJsonProvider implements JsonProvider<Users> {
 
     private final com.bigcloud.djomo.Json djomo = new com.bigcloud.djomo.Json();
 
-    // json-io options are immutable+thread-safe once built; cache one instance per provider
-    // to match how every other library here caches its mapper/parser/serializer.
+    // json-io WriteOptions is immutable+thread-safe once built; cache one instance per provider
+    // to match how every other library here caches its mapper/parser/serializer. Read-side uses
+    // JsonIo.toMaps()/toJava() which manage their own option caches internally.
     private final WriteOptions jsonioWriteOptions = new WriteOptionsBuilder().standardJson().build();
-    private final ReadOptions jsonioReadOptionsMaps = new ReadOptionsBuilder().returnAsNativeJsonObjects().build();
 
     public UsersJsonProvider() {
 
@@ -201,11 +199,6 @@ public WriteOptions jsonioWriteOptions() {
         return jsonioWriteOptions;
     }
 
-    @Override
-    public ReadOptions jsonioReadOptionsMaps() {
-        return jsonioReadOptionsMaps;
-    }
-
     private static final ThreadLocal<QuickbufSchema.Users> QUICKBUF_MESSAGE = ThreadLocal.withInitial(QuickbufSchema.Users::newInstance);
     private static final ThreadLocal<JsonSink> QUICKBUF_SINK = ThreadLocal.withInitial(() -> JsonSink.newInstance()
             .setPrettyPrinting(false)

src/main/java/com/github/fabienrenaud/jjb/stream/Deserialization.java

@@ -13,6 +13,7 @@
 import java.util.concurrent.atomic.AtomicReference;
 
 import com.cedarsoftware.io.JsonIo;
+import com.cedarsoftware.io.JsonObject;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.openjdk.jmh.annotations.Benchmark;
@@ -92,12 +93,14 @@ public Object genson() throws Exception {
     @Benchmark
     @Override
     public Object jsonio() {
-        // returnAsNativeJsonObjects maps to old JsonWriter.USE_MAPS=true behavior,
-        // see {@link JsonIo#getReadOptionsBuilder(java.util.Map)} and
-        // <a href="https://github.com/jdereg/json-io/blob/4.19.1/changelog.md">the v4.19 changelog</a>
-        return JsonIo.toObjects(
-            JSON_SOURCE().nextInputStream(), JSON_SOURCE().provider().jsonioReadOptionsMaps(), null
-        );
+        // toMaps() returns the JsonObject (Map) graph directly via MapResolver,
+        // skipping the second-pass POJO field injection that toJava() does.
+        // ~45% faster on JsonPerformanceTest. The API handles Maps-mode option
+        // configuration internally via its own cache, so no options needed here.
+        // Explicit JsonObject target keeps the result as the native lite Map
+        // representation (the round-trip test in JsonBenchmark.test detects
+        // JsonObject and re-serializes it for verification).
+        return JsonIo.toMaps(JSON_SOURCE().nextInputStream()).asClass(JsonObject.class);
     }
 
     @Benchmark