* New custom ClassFactory classes are easier to write:

    * See [examples](user-guide.md#classfactory-and-customwriter-examples)
  * `ByteBuffer` and `CharBuffer` now natively supported.
  * `CompactMap` supported added via `CompactMapFactory` and `CompactMapWriter`.
  * `Sealable*` tests moved from `java-util` to `json-io` (and so have the `Sealable*` classes).

Author: jdereg

README.md

@@ -31,15 +31,15 @@ ___
 To include in your project:
 ##### Gradle
 ```groovy
-implementation 'com.cedarsoftware:json-io:4.32.0'
+implementation 'com.cedarsoftware:json-io:4.33.0'
 ```
 
 ##### Maven
 ```xml
  <dependency>
    <groupId>com.cedarsoftware</groupId>
    <artifactId>json-io</artifactId>
-   <version>4.32.0</version>
+   <version>4.33.0</version>
  </dependency>
 ```
 ___
@@ -57,23 +57,23 @@ ___
 >- [ ] **Java Package**: com.cedarsoftware.io
 >- [ ] **Java**: JDK17+ (Class file 61 format, includes module-info.class - multi-release JAR)
 >- [ ] **API**
-   >  - Static methods on [JsonIo](https://www.javadoc.io/doc/com.cedarsoftware/json-io/latest/com/cedarsoftware/io/JsonIo.html): [toJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#toJson(java.lang.Object,com.cedarsoftware.io.WriteOptions)), [toObjects()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#toObjects(java.lang.String,com.cedarsoftware.io.ReadOptions,java.lang.Class)), [formatJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#formatJson(java.lang.String,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions)), [deepCopy()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#deepCopy(java.lang.Object,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions))
+   >  - Static methods on [JsonIo](https://www.javadoc.io/doc/com.cedarsoftware/json-io/latest/com/cedarsoftware/io/JsonIo.html): [toJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#toJson(java.lang.Object,com.cedarsoftware.io.WriteOptions)), [toObjects()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#toObjects(java.lang.String,com.cedarsoftware.io.ReadOptions,java.lang.Class)), [formatJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#formatJson(java.lang.String,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions)), [deepCopy()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#deepCopy(java.lang.Object,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions))
 >  - Use [ReadOptionsBuilder](/user-guide-readOptions.md) and [WriteOptionsBuilder](/user-guide-writeOptions.md) to configure `JsonIo`
->  - Use [JsonReader.ClassFactory](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonReader.ClassFactory.html) for difficult classes (hard to instantiate & fill)
->  - Use [JsonWriter.JsonClassWriter](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonWriter.JsonClassWriter.html) to customize the output JSON for a particular class
+>  - Use [JsonReader.ClassFactory](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonReader.ClassFactory.html) for difficult classes (hard to instantiate & fill)
+>  - Use [JsonWriter.JsonClassWriter](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonWriter.JsonClassWriter.html) to customize the output JSON for a particular class
 >- [ ] Updates will be 5.1.0, 5.2.0, ...
->### 4.32.0 (current)
->- [ ] **Version**: [4.32.0](https://www.javadoc.io/doc/com.cedarsoftware/json-io/4.32.0/index.html)
+>### 4.33.0 (current)
+>- [ ] **Version**: [4.33.0](https://www.javadoc.io/doc/com.cedarsoftware/json-io/4.33.0/index.html)
 >- [ ] **Bundling**: Both JPMS (Java Platform Module System) and OSGi (Open Service Gateway initiative)
 >- [ ] **Maintained**: Fully
 >- [ ] **Java Package**: com.cedarsoftware.io
 >- [ ] **Java**: JDK1.8+ (Class file 52 format, includes module-info.class - multi-release JAR)
 >- [ ] **API**
->  - Static methods on [JsonIo](https://www.javadoc.io/doc/com.cedarsoftware/json-io/latest/com/cedarsoftware/io/JsonIo.html): [toJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#toJson(java.lang.Object,com.cedarsoftware.io.WriteOptions)), [toObjects()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#toObjects(java.lang.String,com.cedarsoftware.io.ReadOptions,java.lang.Class)), [formatJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#formatJson(java.lang.String,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions)), [deepCopy()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonIo.html#deepCopy(java.lang.Object,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions))
+>  - Static methods on [JsonIo](https://www.javadoc.io/doc/com.cedarsoftware/json-io/latest/com/cedarsoftware/io/JsonIo.html): [toJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#toJson(java.lang.Object,com.cedarsoftware.io.WriteOptions)), [toObjects()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#toObjects(java.lang.String,com.cedarsoftware.io.ReadOptions,java.lang.Class)), [formatJson()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#formatJson(java.lang.String,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions)), [deepCopy()](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonIo.html#deepCopy(java.lang.Object,com.cedarsoftware.io.ReadOptions,com.cedarsoftware.io.WriteOptions))
 >  - Use [ReadOptionsBuilder](/user-guide-readOptions.md) and [WriteOptionsBuilder](/user-guide-writeOptions.md) to configure `JsonIo`
->  - Use [JsonReader.ClassFactory](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonReader.ClassFactory.html) for difficult classes (hard to instantiate & fill)
->  - Use [JsonWriter.JsonClassWriter](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.32.0/com/cedarsoftware/io/JsonWriter.JsonClassWriter.html) to customize the output JSON for a particular class
->- [ ] Updates will be 4.33.0, 4.34.0, ...
+>  - Use [JsonReader.ClassFactory](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonReader.ClassFactory.html) for difficult classes (hard to instantiate & fill)
+>  - Use [JsonWriter.JsonClassWriter](https://www.javadoc.io/static/com.cedarsoftware/json-io/4.33.0/com/cedarsoftware/io/JsonWriter.JsonClassWriter.html) to customize the output JSON for a particular class
+>- [ ] Updates will be 4.34.0, 4.35.0, ...
 >### 4.14.x (supported)
 >- [ ] **Version**: [4.14.3](https://www.javadoc.io/doc/com.cedarsoftware/json-io/4.14.3/index.html)
 >- [ ] **Bundling**: Both JPMS (Java Platform Module System) and OSGi (Open Service Gateway initiative)

changelog.md

@@ -1,4 +1,10 @@
 ### Revision History
+#### 4.33.0
+  * New custom `ClassFactory` classes are easier to write:
+    * See [examples](user-guide.md#classfactory-and-customwriter-examples)
+  * `ByteBuffer` and `CharBuffer` now natively supported.
+  * `CompactMap` supported added via `CompactMapFactory` and `CompactMapWriter`.
+  * `Sealable*` tests moved from `java-util` to `json-io` (and so have the `Sealable*` classes).
 #### 4.32.0
   * EnumSet can now be written with @type or @enum, controlled by a WriteOption (writeEnumSetOldWay).  Currently, the default is `true,` write the old way for backward compatibility. This will change in a future release.
   * JsonObject simplified, with `@keys` and `@items` now as explicit fields.

pom.xml

@@ -5,7 +5,7 @@
     <groupId>com.cedarsoftware</groupId>
     <artifactId>json-io</artifactId>
     <packaging>bundle</packaging>
-    <version>4.32.0</version>
+    <version>4.33.0</version>
     <description>Java JSON serialization</description>
     <url>https://github.com/jdereg/json-io</url>
 
@@ -27,7 +27,7 @@
         <!-- remove source encoding warnings from maven output -->
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-        <version.java-util>3.0.0</version.java-util>
+        <version.java-util>3.0.2</version.java-util>
         <!-- testing only -->
         <version.junit-jupiter-params>5.11.4</version.junit-jupiter-params>
         <version.assertj-core>3.27.2</version.assertj-core>

src/main/java/com/cedarsoftware/io/JsonIo.java

@@ -489,6 +489,9 @@ public static WriteOptionsBuilder getWriteOptionsBuilder(Map<String, Object> opt
         return builder;
     }
 
+    public static String PREFIX = "-~";
+    public static String SUFFIX = "~-";
+
     //
     // READ Option Keys (older method of specifying options) -----------------------------------------------------------
     //

src/main/java/com/cedarsoftware/io/JsonObject.java

@@ -2,14 +2,13 @@
 
 import java.lang.reflect.Array;
 import java.util.AbstractMap;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.IdentityHashMap;
+import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
-import com.cedarsoftware.util.CompactLinkedMap;
-
 /**
  * This class holds a JSON object in a LinkedHashMap.
  * LinkedHashMap used to keep fields in same order as they are
@@ -34,7 +33,8 @@
  *         limitations under the License.
  */
 public class JsonObject extends JsonValue implements Map<Object, Object> {
-    private final Map<Object, Object> jsonStore = new CompactLinkedMap<>();
+//    private final Map<Object, Object> jsonStore = CompactMap.builder().compactSize(40).insertionOrder().build();
+    private final Map<Object, Object> jsonStore = new LinkedHashMap<>();
     private Integer hash = null;
 
     // Explicit fields for meta data
@@ -187,16 +187,59 @@ private int hashCode(Object array, Map<Object, Integer> seen) {
         return result;
     }
 
+    @Override
     public boolean equals(Object obj) {
         if (this == obj) return true;
         if (!(obj instanceof JsonObject)) return false;
         JsonObject other = (JsonObject) obj;
 
-        if (!Arrays.deepEquals(new Object[]{items}, new Object[]{other.items})) return false;
-        if (!Arrays.deepEquals(new Object[]{keys}, new Object[]{other.keys})) return false;
+        // Compare 'items' shallowly (element-by-element if both are arrays).
+        if (!shallowArrayEquals(this.items, other.items)) {
+            return false;
+        }
+
+        // Compare 'keys' shallowly (element-by-element if both are arrays).
+        if (!shallowArrayEquals(this.keys, other.keys)) {
+            return false;
+        }
+
+        // Compare the Map portion the standard way.
         return jsonStore.equals(other.jsonStore);
     }
 
+    /**
+     * Compare two Objects if both are arrays, element by element,
+     * otherwise do a simple Object.equals().
+     */
+    private static boolean shallowArrayEquals(Object arr1, Object arr2) {
+        if (arr1 == arr2) {
+            return true;            // Same reference or both null
+        }
+        if (arr1 == null || arr2 == null) {
+            return false;           // One is null, the other is not
+        }
+
+        // If both are arrays, compare lengths and elements with .equals()
+        if (arr1.getClass().isArray() && arr2.getClass().isArray()) {
+            int len1 = Array.getLength(arr1);
+            int len2 = Array.getLength(arr2);
+            if (len1 != len2) {
+                return false;
+            }
+            for (int i = 0; i < len1; i++) {
+                Object e1 = Array.get(arr1, i);
+                Object e2 = Array.get(arr2, i);
+                if (!Objects.equals(e1, e2)) {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        // Fallback if not arrays: just do a regular equals check
+        return Objects.equals(arr1, arr2);
+    }
+    
     public boolean isEmpty() {
         return size() < 1;
     }
@@ -304,6 +347,13 @@ void rehashMaps() {
         for (int i = 0; i < len; i++) {
             Object key = Array.get(keys, i);
             Object value = Array.get(items, i);
+            
+            if (key instanceof String) {
+                String k = (String) key;
+                if (k.startsWith(JsonIo.PREFIX) && k.endsWith(JsonIo.SUFFIX)) {
+                    continue;
+                }
+            }
             put(key, value);
             if (targetMap != null) {
                 targetMap.put(key, value);