Workaround JNH InputStream.available() == 1 for no entity

connectors/jnh-connector/src/main/java/org/glassfish/jersey/jnh/connector/JavaNetHttpConnector.java

@@ -55,6 +55,8 @@
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Future;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 
 /**
@@ -253,7 +255,12 @@ private ClientResponse buildClientResponse(ClientRequest request, HttpResponse<I
                 headers.put(headerName, entry.getValue());
             }
         }
-        clientResponse.setEntityStream(response.body());
+        final InputStream body = response.body();
+        try {
+            clientResponse.setEntityStream(body.available() != 1 ? body : new FirstByteCachingStream(body));
+        } catch (IOException ioe) {
+            throw new ProcessingException(ioe);
+        }
         return clientResponse;
     }
 
@@ -329,4 +336,87 @@ private SSLParameters getSslParameters(Client client) {
             }
         }
     }
+
+    /*
+     * The JDK stream returns available() == 1 even when read() == -1
+     * This class is to prevent it.
+     * Otherwise, the MBR is not found for 204
+     * See https://github.com/eclipse-ee4j/jersey/issues/5307
+     */
+    private static class FirstByteCachingStream extends InputStream {
+        private final InputStream inner; //jdk.internal.net.http.ResponseSubscribers.HttpResponseInputStream
+        private volatile int zero = -1; // int on zero index
+        private final Lock lock = new ReentrantLock();
+
+        private FirstByteCachingStream(InputStream inner) {
+            this.inner = inner;
+        }
+
+        @Override
+        public int read() throws IOException {
+            lock.lock();
+            final int r = zero != -1 ? zero : inner.read();
+            zero = -1;
+            lock.unlock();
+            return r;
+        }
+
+        @Override
+        public int read(byte[] b, int off, int len) throws IOException {
+            lock.lock();
+            int r;
+            if (zero != -1) {
+                b[off] = (byte) (zero & 0xFF);
+                r = inner.read(b, off + 1, len - 1);
+            } else {
+                r = inner.read(b, off, len);
+            }
+            zero = -1;
+            lock.unlock();
+            return r;
+
+        }
+
+        @Override
+        public int available() throws IOException {
+            lock.lock();
+            if (zero != -1) {
+                lock.unlock();
+                return 1;
+            }
+
+            int available = inner.available();
+            if (available != 1) {
+                lock.unlock();
+                return available;
+            }
+
+            zero = inner.read();
+            if (zero == -1) {
+                available = 0;
+            }
+            lock.unlock();
+            return available;
+        }
+
+        @Override
+        public void close() throws IOException {
+            inner.close();
+            lock.lock();
+            zero = -1;
+            lock.unlock();
+        }
+
+        @Override
+        public boolean markSupported() {
+            return inner.markSupported();
+        }
+
+        @Override
+        public synchronized void mark(int readlimit) {
+            inner.mark(readlimit);
+        }
+
+    }
+
 }

connectors/jnh-connector/src/test/java/org/glassfish/jersey/jnh/connector/FirstByteCachingStreamTest.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 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
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package org.glassfish.jersey.jnh.connector;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.lang.reflect.Constructor;
+
+class FirstByteCachingStreamTest {
+    private static InputStream createFirstByteCachingStream(InputStream inner) throws Exception {
+        Class[] classes = JavaNetHttpConnector.class.getDeclaredClasses();
+        for (Class<?> clazz : classes) {
+            if (clazz.getName().contains("FirstByteCachingStream")) {
+                Constructor constructor = clazz.getDeclaredConstructor(InputStream.class);
+                constructor.setAccessible(true);
+                return (InputStream) constructor.newInstance(inner);
+            }
+        }
+        throw new IllegalArgumentException("JavaNetHttpConnector inner class FirstByteCachingStream not found");
+    }
+
+    @Test
+    void testNoByte() throws Exception {
+        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(new byte[0]);
+        InputStream testIs = createFirstByteCachingStream(byteArrayInputStream);
+        Assertions.assertEquals(0, testIs.available());
+    }
+
+    @Test
+    void testOneByte() throws Exception {
+        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(new byte[]{'A'});
+        InputStream testIs = createFirstByteCachingStream(byteArrayInputStream);
+        Assertions.assertEquals(1, testIs.available());
+        Assertions.assertEquals(1, testIs.available()); // idempotency
+        Assertions.assertEquals('A', testIs.read());
+        Assertions.assertEquals(0, testIs.available());
+    }
+
+    @Test
+    void testTwoBytes() throws Exception {
+        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(new byte[]{'A', 'B'});
+        InputStream testIs = createFirstByteCachingStream(byteArrayInputStream);
+        Assertions.assertEquals(2, testIs.available());
+        Assertions.assertEquals(2, testIs.available()); // idempotency
+        Assertions.assertEquals('A', testIs.read());
+        Assertions.assertEquals(1, testIs.available());
+        Assertions.assertEquals(1, testIs.available()); // idempotency
+        Assertions.assertEquals('B', testIs.read());
+        Assertions.assertEquals(0, testIs.available());
+    }
+
+    @Test
+    void testTwoBytesReadAtOnce() throws Exception {
+        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(new byte[]{'A', 'B'});
+        InputStream testIs = createFirstByteCachingStream(byteArrayInputStream);
+        Assertions.assertEquals(2, testIs.available());
+
+        byte[] bytes = new byte[2];
+        testIs.read(bytes);
+        Assertions.assertEquals('A', bytes[0]);
+        Assertions.assertEquals('B', bytes[1]);
+        Assertions.assertEquals(0, testIs.available());
+    }
+}

connectors/jnh-connector/src/test/java/org/glassfish/jersey/jnh/connector/NoEntityTest.java

@@ -16,6 +16,7 @@
 
 package org.glassfish.jersey.jnh.connector;
 
+import jakarta.ws.rs.core.GenericType;
 import org.glassfish.jersey.client.ClientConfig;
 import org.glassfish.jersey.logging.LoggingFeature;
 import org.glassfish.jersey.server.ResourceConfig;
@@ -44,6 +45,13 @@ public Response get() {
         @POST
         public void post(String entity) {
         }
+
+        @GET
+        @Path("/success")
+        public Response getSuccessfully() {
+            return Response.status(Response.Status.NO_CONTENT).build();
+        }
+
     }
 
     @Override
@@ -77,6 +85,32 @@ public void testGetWithClose() {
         }
     }
 
+    @Test
+    public void testGetVoidWithClose() {
+        WebTarget r = target("test");
+        for (int i = 0; i < 5; i++) {
+            Response cr = r.request().get();
+            cr.close();
+        }
+    }
+
+    @Test
+    public void testGetVoid() {
+        WebTarget r = target("test/success");
+        for (int i = 0; i < 5; i++) {
+            r.request().get(void.class);
+        }
+    }
+
+    @Test
+    public void testGetGenericVoid() {
+        WebTarget r = target("test/success");
+        for (int i = 0; i < 5; i++) {
+            r.request().get(new GenericType<Void>() {
+            });
+        }
+    }
+
     @Test
     public void testPost() {
         WebTarget r = target("test");