Updating to work with java 1.6

src/main/java/org/json/InstanceCreator.java

@@ -0,0 +1,16 @@
+package org.json;
+
+/**
+ * Interface defining a creator that produces new instances of type {@code T}.
+ *
+ * @param <T> the type of instances created
+ */
+public interface InstanceCreator<T> {
+
+  /**
+   * Creates a new instance of type {@code T}.
+   *
+   * @return a new instance of {@code T}
+   */
+  T create();
+}

src/main/java/org/json/JSONBuilder.java

@@ -7,8 +7,6 @@ import java.util.ArrayList;
 import java.util.Set;
 import java.util.HashSet;
 import java.util.Collection;
-import java.util.function.Function;
-import java.util.function.Supplier;
 
 /**
  * The {@code JSONBuilder} class provides a configurable mechanism for
@@ -42,38 +40,88 @@ public class JSONBuilder {
    *   <li>{@code String.class} -> Identity function</li>
    * </ul>
    */
-  private static final Map<Class<?>, Function<Object, ?>> classMapping = new HashMap<>();
+  private static final Map<Class<?>,  TypeConverter<?>> classMapping = new HashMap<>();
 
   /**
    * A mapping from collection interface types to suppliers that produce
    * instances of concrete collection implementations.
    *
-   * <p>Examples of default mappings:
-   * <ul>
-   *   <li>{@code List.class} -> {@code ArrayList::new}</li>
-   *   <li>{@code Set.class} -> {@code HashSet::new}</li>
-   *   <li>{@code Map.class} -> {@code HashMap::new}</li>
-   * </ul>
    */
-  private static final Map<Class<?>, Supplier<?>> collectionMapping = new HashMap<>();
+  private static final Map<Class<?>, InstanceCreator<?>> collectionMapping = new HashMap<>();
   
    // Static initializer block to populate default mappings
    static {
-    classMapping.put(int.class, s -> ((Number) s).intValue());
-    classMapping.put(Integer.class, s -> ((Number) s).intValue());
-    classMapping.put(double.class, s -> ((Number) s).doubleValue());
-    classMapping.put(Double.class, s -> ((Number) s).doubleValue());
-    classMapping.put(float.class, s -> ((Number) s).floatValue());
-    classMapping.put(Float.class, s -> ((Number) s).floatValue());
-    classMapping.put(long.class, s -> ((Number) s).longValue());
-    classMapping.put(Long.class, s -> ((Number) s).longValue());
-    classMapping.put(boolean.class, s -> s);
-    classMapping.put(Boolean.class, s -> s);
-    classMapping.put(String.class, s -> s);
+    classMapping.put(int.class, new TypeConverter<Integer>() {
+      public Integer convert(Object input) {
+        return ((Number) input).intValue();
+      }
+    });
+    classMapping.put(Integer.class, new TypeConverter<Integer>() {
+      public Integer convert(Object input) {
+        return ((Number) input).intValue();
+      }
+    });
+    classMapping.put(double.class, new TypeConverter<Double>() {
+      public Double convert(Object input) {
+        return ((Number) input).doubleValue();
+      }
+    });
+    classMapping.put(Double.class, new TypeConverter<Double>() {
+      public Double convert(Object input) {
+        return ((Number) input).doubleValue();
+      }
+    });
+    classMapping.put(float.class, new TypeConverter<Float>() {
+      public Float convert(Object input) {
+        return ((Number) input).floatValue();
+      }
+    });
+    classMapping.put(Float.class, new TypeConverter<Float>() {
+      public Float convert(Object input) {
+        return ((Number) input).floatValue();
+      }
+    });
+    classMapping.put(long.class, new TypeConverter<Long>() {
+      public Long convert(Object input) {
+        return ((Number) input).longValue();
+      }
+    });
+    classMapping.put(Long.class, new TypeConverter<Long>() {
+      public Long convert(Object input) {
+        return ((Number) input).longValue();
+      }
+    });
+    classMapping.put(boolean.class, new TypeConverter<Boolean>() {
+      public Boolean convert(Object input) {
+        return (Boolean) input;
+      }
+    });
+    classMapping.put(Boolean.class, new TypeConverter<Boolean>() {
+      public Boolean convert(Object input) {
+        return (Boolean) input;
+      }
+    });
+    classMapping.put(String.class, new TypeConverter<String>() {
+      public String convert(Object input) {
+        return (String) input;
+      }
+    });
 
-    collectionMapping.put(List.class, ArrayList::new);
-    collectionMapping.put(Set.class, HashSet::new);
-    collectionMapping.put(Map.class, HashMap::new);
+    collectionMapping.put(List.class, new InstanceCreator<List>() {
+      public List create() {
+        return new ArrayList();
+      }
+    });
+    collectionMapping.put(Set.class, new InstanceCreator<Set>() {
+      public Set create() {
+        return new HashSet();
+      }
+    });
+    collectionMapping.put(Map.class, new InstanceCreator<Map>() {
+      public Map create() {
+        return new HashMap(); 
+      }
+    });
    }
 
   /**
@@ -81,7 +129,7 @@ public class JSONBuilder {
    *
    * @return a map of classes to functions that convert an {@code Object} to that class
    */
-   public Map<Class<?>, Function<Object, ?>> getClassMapping() {
+   public Map<Class<?>, TypeConverter<?>> getClassMapping() {
      return this.classMapping;
    }
 
@@ -90,7 +138,7 @@ public class JSONBuilder {
    *
    * @return a map of collection interface types to suppliers of concrete implementations
    */
-   public Map<Class<?>, Supplier<?>> getCollectionMapping() {
+   public Map<Class<?>, InstanceCreator<?>> getCollectionMapping() {
      return this.collectionMapping;
    }
 
@@ -103,7 +151,7 @@ public class JSONBuilder {
    * @param clazz the target class for which the conversion function is to be set
    * @param function a function that takes an {@code Object} and returns an instance of {@code clazz}
    */
-   public void setClassMapping(Class<?> clazz, Function<Object, ?> function) {
+   public void setClassMapping(Class<?> clazz, TypeConverter<?> function) {
      classMapping.put(clazz, function);
    }
 
@@ -116,7 +164,7 @@ public class JSONBuilder {
    * @param clazz the collection interface class (e.g., {@code List.class})
    * @param function a supplier that creates a new instance of a concrete implementation
    */
-   public void setCollectionMapping(Class<?> clazz, Supplier<?> function) {
+   public void setCollectionMapping(Class<?> clazz, InstanceCreator<?> function) {
      collectionMapping.put(clazz, function);
    }
 }

src/main/java/org/json/JSONObject.java

@@ -3256,7 +3256,7 @@ public class JSONObject {
         if (this.builder == null) {
           this.builder = new JSONBuilder();
         }
-        Map<Class<?>, Function<Object, ?>> classMapping = this.builder.getClassMapping();
+        Map<Class<?>, TypeConverter<?>> classMapping = this.builder.getClassMapping();
 
         for (Field field: clazz.getDeclaredFields()) {
           field.setAccessible(true);
@@ -3265,7 +3265,7 @@ public class JSONObject {
             Object value = this.get(fieldName);
             Class<?> pojoClass = field.getType();
             if (classMapping.containsKey(pojoClass)) {
-              field.set(obj, classMapping.get(pojoClass).apply(value));
+              field.set(obj, classMapping.get(pojoClass).convert(value));
             } else {
               if (value.getClass() == JSONObject.class) {
                 field.set(obj, fromJson((JSONObject) value, pojoClass));
@@ -3290,10 +3290,10 @@ public class JSONObject {
 
     private <T> Collection<T> fromJsonArray(JSONArray jsonArray, Class<?> collectionType, Type elementType) throws JSONException {
       try {
-        Map<Class<?>, Function<Object, ?>> classMapping = this.builder.getClassMapping();
-        Map<Class<?>, Supplier<?>> collectionMapping = this.builder.getCollectionMapping();
+        Map<Class<?>, TypeConverter<?>> classMapping = this.builder.getClassMapping();
+        Map<Class<?>, InstanceCreator<?>> collectionMapping = this.builder.getCollectionMapping();
         Collection<T> collection = (Collection<T>) (collectionMapping.containsKey(collectionType) ? 
-            collectionMapping.get(collectionType).get() 
+            collectionMapping.get(collectionType).create() 
             : collectionType.getDeclaredConstructor().newInstance());
 
 
@@ -3312,7 +3312,7 @@ public class JSONObject {
         for (int i = 0; i < jsonArray.length(); i++) {
           Object jsonElement = jsonArray.get(i);
           if (classMapping.containsKey(innerElementClass)) {
-            collection.add((T) classMapping.get(innerElementClass).apply(jsonElement));
+            collection.add((T) classMapping.get(innerElementClass).convert(jsonElement));
           } else if (jsonElement.getClass() == JSONObject.class) {
             collection.add((T) ((JSONObject) jsonElement).fromJson(innerElementClass));
           } else if (jsonElement.getClass() == JSONArray.class) {

src/main/java/org/json/TypeConverter.java

@@ -0,0 +1,18 @@
+package org.json;
+
+/**
+ * Interface defining a converter that converts an input {@code Object} 
+ * into an instance of a specific type {@code T}.
+ *
+ * @param <T> the target type to convert to
+ */
+public interface TypeConverter<T> {
+
+  /**
+   * Converts the given input object to an instance of type {@code T}.
+   *
+   * @param input the object to convert
+   * @return the converted instance of type {@code T}
+   */
+  T convert(Object input);
+}

src/test/java/org/json/junit/JSONObjectTest.java

@@ -37,6 +37,7 @@ import org.json.JSONBuilder;
 import org.json.JSONTokener;
 import org.json.ParserConfiguration;
 import org.json.XML;
+import org.json.TypeConverter;
 import org.json.junit.data.BrokenToString;
 import org.json.junit.data.ExceptionalBean;
 import org.json.junit.data.Fraction;
@@ -4133,7 +4134,11 @@ public class JSONObjectTest {
     @Test
     public void jsonObjectParseFromJson_1() {
       JSONBuilder builder = new JSONBuilder();
-      builder.setClassMapping(java.time.LocalDateTime.class, s -> java.time.LocalDateTime.parse((String)s));
+      builder.setClassMapping(java.time.LocalDateTime.class, new TypeConverter<java.time.LocalDateTime>() {
+        public java.time.LocalDateTime convert(Object input) {
+          return java.time.LocalDateTime.parse((String) input);
+        }
+      });
       JSONObject object = new JSONObject(builder);
       java.time.LocalDateTime localDateTime = java.time.LocalDateTime.now();
       object.put("localDate", localDateTime.toString());