Fix memory leak in AbstractJackson2Encoder

poutsma · poutsma · commit 857b6006758e · 2018-10-18T17:09:53.000+02:00
Fixes a DataBuffer memory leak where a created buffer was not release
if Jackson threw an exception.
diff --git a/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java b/spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java
@@ -44,6 +44,7 @@
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.HttpMessageEncoder;
@@ -161,11 +162,14 @@ private DataBuffer encodeValue(Object value, @Nullable MimeType mimeType, DataBu
 		writer = customizeWriter(writer, mimeType, elementType, hints);
 
 		DataBuffer buffer = bufferFactory.allocateBuffer();
+		boolean release = true;
 		OutputStream outputStream = buffer.asOutputStream();
 
 		try {
-			JsonGenerator generator = getObjectMapper().getFactory().createGenerator(outputStream, encoding);
+			JsonGenerator generator =
+					getObjectMapper().getFactory().createGenerator(outputStream, encoding);
 			writer.writeValue(generator, value);
+			release = false;
 		}
 		catch (InvalidDefinitionException ex) {
 			throw new CodecException("Type definition error: " + ex.getType(), ex);
@@ -174,7 +178,13 @@ private DataBuffer encodeValue(Object value, @Nullable MimeType mimeType, DataBu
 			throw new EncodingException("JSON encoding error: " + ex.getOriginalMessage(), ex);
 		}
 		catch (IOException ex) {
-			throw new IllegalStateException("Unexpected I/O error while writing to data buffer", ex);
+			throw new IllegalStateException("Unexpected I/O error while writing to data buffer",
+					ex);
+		}
+		finally {
+			if (release) {
+				DataBufferUtils.release(buffer);
+			}
 		}
 
 		return buffer;
