Keeping ReaderWriter.writeTo, can fallback to original custom code by…

… explicitly setting org.glassfish.jersey.message.MessageProperties#IO_BUFFER_SIZE

connectors/apache-connector/src/main/java/org/glassfish/jersey/apache/connector/ApacheConnector.java

@@ -740,7 +740,8 @@ private static InputStream getInputStream(final CloseableHttpResponse response,
             if (i.markSupported()) {
                 inputStream = i;
             } else {
-                inputStream = new BufferedInputStream(i, ReaderWriter.BUFFER_SIZE);
+                inputStream = ReaderWriter.BUFFER_SIZE == -1 ? new BufferedInputStream(i)
+                        : new BufferedInputStream(i, ReaderWriter.BUFFER_SIZE);
             }
         }
 

connectors/apache5-connector/src/main/java/org/glassfish/jersey/apache5/connector/Apache5Connector.java

@@ -751,7 +751,8 @@ private static InputStream getInputStream(final CloseableHttpResponse response,
             if (i.markSupported()) {
                 inputStream = i;
             } else {
-                inputStream = new BufferedInputStream(i, ReaderWriter.BUFFER_SIZE);
+                inputStream = ReaderWriter.BUFFER_SIZE == -1 ? new BufferedInputStream(i)
+                        : new BufferedInputStream(i, ReaderWriter.BUFFER_SIZE);
             }
         }
 

core-common/src/main/java/org/glassfish/jersey/message/MessageProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2023 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -67,18 +67,12 @@ public final class MessageProperties {
      * on byte and character streams. The property value is expected to be a positive
      * integer otherwise it will be ignored.
      * <p />
-     * The default value is <code>{@value #IO_DEFAULT_BUFFER_SIZE}</code>.
+     * The default value is decided by the JRE.
      * <p />
      * The name of the configuration property is <code>{@value}</code>.
      */
     public static final String IO_BUFFER_SIZE = "jersey.config.io.bufferSize";
 
-    /**
-     * The default buffer size ({@value}) for I/O operations on byte and character
-     * streams.
-     */
-    public static final int IO_DEFAULT_BUFFER_SIZE = 8192;
-
     /**
      * If set to {@code true}, {@code DeflateEncoder deflate encoding interceptor} will use non-standard version
      * of the deflate content encoding, skipping the zlib wrapper. Unfortunately, deflate encoding

core-common/src/main/java/org/glassfish/jersey/message/internal/AbstractMessageReaderWriterProvider.java

@@ -44,7 +44,7 @@ public abstract class AbstractMessageReaderWriterProvider<T> implements MessageB
     /**
      * The UTF-8 Charset.
      *
-     * @deprecated use {@code StandardCharsets.UTF8} instead.
+     * @deprecated use {@code StandardCharsets.UTF_8} instead.
      */
     @Deprecated(forRemoval = true)
     public static final Charset UTF8 = StandardCharsets.UTF_8;
@@ -56,11 +56,11 @@ public abstract class AbstractMessageReaderWriterProvider<T> implements MessageB
      * @param out the output stream to write to.
      * @throws IOException if there is an error reading or writing bytes.
      *
-     * @deprecated use {@code in.transferTo(out)} instead.
+     * @deprecated use {@code ReaderWriter.writeTo(in, out)} instead.
      */
     @Deprecated
     public static void writeTo(InputStream in, OutputStream out) throws IOException {
-        in.transferTo(out);
+        ReaderWriter.writeTo(in, out);
     }
 
     /**
@@ -70,11 +70,11 @@ public static void writeTo(InputStream in, OutputStream out) throws IOException
      * @param out the writer to write to.
      * @throws IOException if there is an error reading or writing characters.
      *
-     * @deprecated use {@code in.transferTo(out)} instead.
+     * @deprecated use {@code ReaderWriter.writeTo(in, out)} instead.
      */
     @Deprecated
     public static void writeTo(Reader in, Writer out) throws IOException {
-        in.transferTo(out);
+        ReaderWriter.writeTo(in, out);
     }
 
     /**

core-common/src/main/java/org/glassfish/jersey/message/internal/DataSourceProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2020 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -75,7 +75,7 @@ public int getCount() {
 
         public ByteArrayDataSource(final InputStream is, final String type) throws IOException {
             final DSByteArrayOutputStream os = new DSByteArrayOutputStream();
-            is.transferTo(os);
+            ReaderWriter.writeTo(is, os);
             this.data = os.getBuf();
             this.len = os.getCount();
 

core-common/src/main/java/org/glassfish/jersey/message/internal/InboundMessageContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2022 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -960,7 +960,7 @@ public boolean bufferEntity() throws ProcessingException {
             final InputStream entityStream = entityContent.getWrappedStream();
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
             try {
-                entityStream.transferTo(baos);
+                ReaderWriter.writeTo(entityStream, baos);
             } finally {
                 // Workaround for JRFCAF-1344: the underlying stream close() implementation may be thread-unsafe
                 // and as such the close() may result in an IOException at the socket input stream level,

core-common/src/main/java/org/glassfish/jersey/message/internal/InputStreamProvider.java

@@ -79,7 +79,7 @@ public void writeTo(
             MultivaluedMap<String, Object> httpHeaders,
             OutputStream entityStream) throws IOException {
         try (t) {
-            t.transferTo(entityStream);
+            writeTo(t, entityStream);
         }
     }
 }

core-common/src/main/java/org/glassfish/jersey/message/internal/ReaderWriter.java

@@ -41,7 +41,7 @@
  * A utility class for reading and writing using byte and character streams.
  * <p>
  * If a byte or character array is utilized then the size of the array
- * is by default the value of {@value org.glassfish.jersey.message.MessageProperties#IO_DEFAULT_BUFFER_SIZE}.
+ * is by default decided by the JRE.
  * This value can be set using the system property
  * {@value org.glassfish.jersey.message.MessageProperties#IO_BUFFER_SIZE}.
  *
@@ -59,6 +59,7 @@ public final class ReaderWriter {
     public static final Charset UTF8 = StandardCharsets.UTF_8;
     /**
      * The buffer size for arrays of byte and character.
+     * A value of {@value -1} means that the JRE will decide the buffer size.
      */
     public static final int BUFFER_SIZE = getBufferSize();
 
@@ -76,11 +77,11 @@ private static int getBufferSize() {
                 LOGGER.log(Level.CONFIG,
                         "Value of " + MessageProperties.IO_BUFFER_SIZE
                                 + " property is not a valid positive integer [" + value + "]."
-                                + " Reverting to default [" + MessageProperties.IO_DEFAULT_BUFFER_SIZE + "].",
+                                + " Reverting to default [at JRE's discretion].",
                         e);
             }
         }
-        return MessageProperties.IO_DEFAULT_BUFFER_SIZE;
+        return -1;
     }
 
     /**
@@ -89,12 +90,18 @@ private static int getBufferSize() {
      * @param in  the input stream to read from.
      * @param out the output stream to write to.
      * @throws IOException if there is an error reading or writing bytes.
-     *
-     * @deprecated use {@code in.transferTo(out)} instead
      */
-    @Deprecated(forRemoval = true)
     public static void writeTo(InputStream in, OutputStream out) throws IOException {
-        in.transferTo(out);
+        if (BUFFER_SIZE == -1) {
+            in.transferTo(out);
+            return;
+        }
+
+        int read;
+        final byte[] data = new byte[BUFFER_SIZE];
+        while ((read = in.read(data)) != -1) {
+            out.write(data, 0, read);
+        }
     }
 
     /**
@@ -103,12 +110,18 @@ public static void writeTo(InputStream in, OutputStream out) throws IOException
      * @param in  the reader to read from.
      * @param out the writer to write to.
      * @throws IOException if there is an error reading or writing characters.
-     *
-     * @deprecated use {@code in.transferTo(out)} instead
      */
-    @Deprecated(forRemoval = true)
     public static void writeTo(Reader in, Writer out) throws IOException {
-        in.transferTo(out);
+        if (BUFFER_SIZE == -1) {
+            in.transferTo(out);
+            return;
+        }
+
+        int read;
+        final char[] data = new char[BUFFER_SIZE];
+        while ((read = in.read(data)) != -1) {
+            out.write(data, 0, read);
+        }
     }
 
     /**

core-common/src/test/java/org/glassfish/jersey/message/internal/UtilsTest.java

@@ -34,7 +34,7 @@ public void createTempFile() throws IOException {
 
         try (final OutputStream stream = new BufferedOutputStream(Files.newOutputStream(file.toPath()))) {
             final ByteArrayInputStream entityStream = new ByteArrayInputStream("Test stream byte input".getBytes());
-            entityStream.transferTo(stream);
+            ReaderWriter.writeTo(entityStream, stream);
         }
         Assertions.assertTrue(file.exists());
     }

examples/sse-twitter-aggregator/src/main/java/org/glassfish/jersey/examples/aggregator/App.java

@@ -241,7 +241,7 @@ public void service(Request request, Response response) throws Exception {
             } else {
                 response.setStatus(HttpStatus.OK_200);
                 response.setContentType(mediaType);
-                fileStream.transferTo(response.getOutputStream());
+                ReaderWriter.writeTo(fileStream, response.getOutputStream());
             }
         }
     }

incubator/html-json/src/test/java/org/glassfish/jersey/media/htmljson/AbstractTypeTester.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2022 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -153,7 +153,7 @@ protected static void _verify(byte[] in, byte[] out) {
     protected static byte[] getEntityAsByteArray(Response r) {
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         try {
-            r.readEntity(InputStream.class).transferTo(baos);
+            ReaderWriter.writeTo(r.readEntity(InputStream.class), baos);
         } catch (IOException e) {
             e.printStackTrace();
         }

tests/e2e-client/src/test/java/org/glassfish/jersey/tests/e2e/client/ChunkedInputStreamClosedPrematurelyTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2022 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -189,7 +189,7 @@ public void testInterruptedJerseyHttpUrlConnection() throws Exception {
             connection.setDoOutput(true);
             connection.setChunkedStreamingMode(1024);
             OutputStream entityStream = connection.getOutputStream();
-            new ExceptionThrowingInputStream(BYTES_TO_SEND).transferTo(entityStream);
+            ReaderWriter.writeTo(new ExceptionThrowingInputStream(BYTES_TO_SEND), entityStream);
             Assertions.fail("Expected ProcessingException has not been thrown.");
         } catch (IOException expected) {
             // so far so good

tests/e2e-core-common/src/test/java/org/glassfish/jersey/tests/e2e/common/message/internal/ReaderWriterTest.java

@@ -29,7 +29,7 @@ public class ReaderWriterTest {
     @Test
     public void testToNeverAskToReadZeroBytes() throws IOException {
         // Unnamed app server bug test
-        int size = ((ReaderWriter.BUFFER_SIZE + 1000) / 10) * 10;
+        int size = (((ReaderWriter.BUFFER_SIZE == -1 ? 8192 : ReaderWriter.BUFFER_SIZE) + 1000) / 10) * 10;
         StringBuilder sb = new StringBuilder(size);
         String shortMsg = "0123456789";
         while (sb.length() < size) {

tests/e2e-entity/src/test/java/org/glassfish/jersey/tests/e2e/entity/AbstractTypeTester.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2022 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -174,7 +174,7 @@ protected static void _verify(byte[] in, byte[] out) {
     protected static byte[] getEntityAsByteArray(Response r) {
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         try {
-            r.readEntity(InputStream.class).transferTo(baos);
+            ReaderWriter.writeTo(r.readEntity(InputStream.class), baos);
         } catch (IOException e) {
             e.printStackTrace();
         }