Fix #3130

FasterXML · Apr 24, 2021 · 4299ccc · 4299ccc
1 parent c6607d1
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diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
@@ -30,6 +30,8 @@ Project: jackson-databind
 #3117: Use more limiting default visibility settings for JDK types (java.*, javax.*)
 #3122: Deep merge for `JsonNode` using `ObjectReader.readTree()`
  (reported by Eric S)
+#3130: Serializing java.lang.Thread fails on JDK 11 and above (should suppress
+  serialization of ClassLoader)
 - Fix to avoid problem with `BigDecimalNode`, scale of `Integer.MIN_VALUE` (see
   [dataformats-binary#264] for details)
 

diff --git a/src/main/java/com/fasterxml/jackson/databind/ser/BasicSerializerFactory.java b/src/main/java/com/fasterxml/jackson/databind/ser/BasicSerializerFactory.java
@@ -475,6 +475,10 @@ protected final JsonSerializer<?> findSerializerByPrimaryType(SerializerProvider
             }
             return NumberSerializer.instance;
         }
+        // 23-Apr-2021, tatu: [databind#3130]: Suppress ClassLoader...
+        if (ClassLoader.class.isAssignableFrom(raw)) {
+            return new ToEmptyObjectSerializer(type);
+        }
         return null;
     }
 

diff --git a/src/main/java/com/fasterxml/jackson/databind/ser/impl/UnknownSerializer.java b/src/main/java/com/fasterxml/jackson/databind/ser/impl/UnknownSerializer.java
@@ -4,49 +4,43 @@
 import java.lang.reflect.Type;
 
 import com.fasterxml.jackson.core.*;
-import com.fasterxml.jackson.core.type.WritableTypeId;
+
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
 import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
-import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+import com.fasterxml.jackson.databind.ser.std.ToEmptyObjectSerializer;
 
 @SuppressWarnings("serial")
 public class UnknownSerializer
-    extends StdSerializer<Object>
+    extends ToEmptyObjectSerializer // since 2.13
 {
     public UnknownSerializer() {
         super(Object.class);
     }
 
-    /**
-     * @since 2.6
-     */
+    // @since 2.6
     public UnknownSerializer(Class<?> cls) {
-        super(cls, false);
+        super(cls);
     }
-    
+
     @Override
-    public void serialize(Object value, JsonGenerator gen, SerializerProvider provider) throws IOException
+    public void serialize(Object value, JsonGenerator gen, SerializerProvider ctxt) throws IOException
     {
         // 27-Nov-2009, tatu: As per [JACKSON-201] may or may not fail...
-        if (provider.isEnabled(SerializationFeature.FAIL_ON_EMPTY_BEANS)) {
-            failForEmpty(provider, value);
+        if (ctxt.isEnabled(SerializationFeature.FAIL_ON_EMPTY_BEANS)) {
+            failForEmpty(ctxt, value);
         }
-        // But if it's fine, we'll just output empty JSON Object:
-        gen.writeStartObject(value, 0);
-        gen.writeEndObject();
+        super.serialize(value, gen, ctxt);
     }
 
     @Override
-    public final void serializeWithType(Object value, JsonGenerator gen, SerializerProvider provider,
+    public void serializeWithType(Object value, JsonGenerator gen, SerializerProvider ctxt,
             TypeSerializer typeSer) throws IOException
     {
-        if (provider.isEnabled(SerializationFeature.FAIL_ON_EMPTY_BEANS)) {
-            failForEmpty(provider, value);
+        if (ctxt.isEnabled(SerializationFeature.FAIL_ON_EMPTY_BEANS)) {
+            failForEmpty(ctxt, value);
         }
-        WritableTypeId typeIdDef = typeSer.writeTypePrefix(gen,
-                typeSer.typeId(value, JsonToken.START_OBJECT));
-        typeSer.writeTypeSuffix(gen, typeIdDef);
+        super.serializeWithType(value, gen, ctxt, typeSer);
     }
 
     @Override

diff --git a/src/main/java/com/fasterxml/jackson/databind/ser/std/ToEmptyObjectSerializer.java b/src/main/java/com/fasterxml/jackson/databind/ser/std/ToEmptyObjectSerializer.java
@@ -0,0 +1,73 @@
+package com.fasterxml.jackson.databind.ser.std;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonToken;
+import com.fasterxml.jackson.core.type.WritableTypeId;
+
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
+import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
+import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
+
+/**
+ * Simple "bogus" serializer that will just serialize an empty
+ * Object for any given value.
+ * Quite similar to {@code UnknownSerializer} with the exception that
+ * serialization never fails.
+ *
+ * @since 2.13
+ */
+@JacksonStdImpl
+@SuppressWarnings("serial")
+public class ToEmptyObjectSerializer
+    extends StdSerializer<Object>
+{
+    protected ToEmptyObjectSerializer(Class<?> raw) {
+        super(raw, false);
+    }
+
+    public ToEmptyObjectSerializer(JavaType type) {
+        super(type);
+    }
+
+    @Override
+    public void serialize(Object value, JsonGenerator gen, SerializerProvider ctxt) throws IOException
+    {
+        gen.writeStartObject(value, 0);
+        gen.writeEndObject();
+    }
+
+    @Override
+    public void serializeWithType(Object value, JsonGenerator gen,
+            SerializerProvider ctxt, TypeSerializer typeSer) throws IOException
+    {
+        WritableTypeId typeIdDef = typeSer.writeTypePrefix(gen,
+                typeSer.typeId(value, JsonToken.START_OBJECT));
+        typeSer.writeTypeSuffix(gen, typeIdDef);
+    }
+
+    @Override
+    public boolean isEmpty(SerializerProvider provider, Object value) {
+        return true;
+    }
+
+    @Override
+    public JsonNode getSchema(SerializerProvider provider, Type typeHint)
+            throws JsonMappingException {
+        return null;
+    }
+
+    @Override
+    public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor,
+            JavaType typeHint)
+        throws JsonMappingException
+    {
+        /*JsonObjectFormatVisitor v =*/ visitor.expectObjectFormat(typeHint);
+    }
+}
diff --git a/src/test/java/com/fasterxml/jackson/databind/ser/jdk/JDKTypeSerializationTest.java b/src/test/java/com/fasterxml/jackson/databind/ser/jdk/JDKTypeSerializationTest.java
@@ -199,4 +199,19 @@ public void testNonStandardProperties() throws Exception
         String json = MAPPER.writeValueAsString(properties);
         assertEquals("{\"key\":1}", json);
     }
+
+    // [databind#3130]: fails on JDK 11+
+    public void testThreadSerialization() throws Exception
+    {
+        final Thread input = Thread.currentThread();
+//        String json = MAPPER.writerWithDefaultPrettyPrinter()
+//                .writeValueAsString(input);
+        Map<?,?> asMap = MAPPER.convertValue(input, Map.class);
+//        System.err.println("PROPS -> "+asMap.keySet());
+
+        // Should get empty "contextClassLoader"
+        Map<?,?> cl = (Map<?,?>) asMap.get("contextClassLoader");
+        assertNotNull(cl);
+        assertEquals(0, cl.size());
+    }
 }