Inconsistent handling of invalid and empty strings for numeric parame…

core-common/src/main/java/org/glassfish/jersey/internal/inject/ParamConverters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2022 Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018 Payara Foundation and/or its affiliates.
  *
  * This program and the accompanying materials are made available under the
@@ -279,11 +279,15 @@ public T fromString(String value) {
                     } else {
                         final List<ClassTypePair> ctps = ReflectionHelper.getTypeArgumentAndClass(genericType);
                         final ClassTypePair ctp = (ctps.size() == 1) ? ctps.get(0) : null;
-
+                        final boolean empty = value.isEmpty();
                         for (ParamConverterProvider provider : Providers.getProviders(manager, ParamConverterProvider.class)) {
                             final ParamConverter<?> converter = provider.getConverter(ctp.rawClass(), ctp.type(), annotations);
                             if (converter != null) {
-                                return (T) Optional.of(value).map(s -> converter.fromString(value));
+                                if (empty) {
+                                    return (T) Optional.empty();
+                                } else {
+                                    return (T) Optional.of(value).map(s -> converter.fromString(value));
+                                }
                             }
                         }
                         /*
@@ -322,7 +326,7 @@ public <T> ParamConverter<T> getConverter(Class<T> rawType, Type genericType, An
 
                 @Override
                 public T fromString(String value) {
-                    if (value == null) {
+                    if (value == null || value.isEmpty()) {
                         return (T) optionals.empty();
                     } else {
                         return (T) optionals.of(value);

tests/e2e-server/src/test/java/org/glassfish/jersey/tests/e2e/server/Issue4790Test.java

@@ -0,0 +1,185 @@
+/*
+ * Copyright (c) 2021, 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
+ * 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.tests.e2e.server;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Application;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+
+import org.glassfish.jersey.server.ResourceConfig;
+import org.glassfish.jersey.test.JerseyTest;
+import org.junit.Test;
+
+public class Issue4790Test extends JerseyTest {
+
+    @Override
+    protected Application configure() {
+        return new ResourceConfig(TestResource.class);
+    }
+
+    @Test
+    public void testString() {
+        String paramMissing = target("/string").request().get(String.class);
+        assertEquals("null", paramMissing);
+
+        String paramProvided = target("/string").queryParam("s", "42").request().get(String.class);
+        assertEquals("s was 42", paramProvided);
+
+        String paramEmpty = target("/string").queryParam("s", "").request().get(String.class);
+        assertEquals("s was ", paramEmpty);
+    }
+
+    @Test
+    public void testOptionalInteger() {
+        String paramMissing = target("/optionalInteger").request().get(String.class);
+        assertEquals("default", paramMissing);
+
+        String paramProvided = target("/optionalInteger").queryParam("i", 42).request().get(String.class);
+        assertEquals("i was 42", paramProvided);
+
+        Response paramInvalidResponse = target("/optionalInteger").queryParam("i", "not-a-number").request().get();
+        assertEquals(404, paramInvalidResponse.getStatus());
+
+        Response paramEmptyResponse = target("/optionalInteger").queryParam("i", "").request().get();
+        assertEquals(200, paramEmptyResponse.getStatus());
+    }
+
+    @Test
+    public void testInteger() {
+        String paramMissing = target("/integer").request().get(String.class);
+        assertEquals("null", paramMissing);
+
+        String paramProvided = target("/integer").queryParam("i", 42).request().get(String.class);
+        assertEquals("i was 42", paramProvided);
+
+        Response paramInvalidResponse = target("/integer").queryParam("i", "not-a-number").request().get();
+        assertEquals(404, paramInvalidResponse.getStatus());
+
+        Response paramEmptyResponse = target("/integer").queryParam("i", "").request().get();
+        assertEquals(200, paramEmptyResponse.getStatus());
+    }
+
+    @Test
+    public void testPrimitiveInt() {
+        String paramMissing = target("/int").request().get(String.class);
+        assertEquals("i was 0", paramMissing);
+
+        String paramProvided = target("/int").queryParam("i", 42).request().get(String.class);
+        assertEquals("i was 42", paramProvided);
+
+        Response paramInvalidResponse = target("/int").queryParam("i", "not-a-number").request().get();
+        assertEquals(404, paramInvalidResponse.getStatus());
+
+        String paramEmpty = target("/int").queryParam("i", "").request().get(String.class);
+        assertEquals("i was 0", paramEmpty);
+    }
+
+    @Test
+    public void emptyStringQueryParamReturnsListWithOneNullElement() {
+        Response response = target("/uuid")
+            .queryParam("list", "")
+            .request()
+            .get();
+        assertEquals(200, response.getStatus());
+        assertEquals("1: [null]",
+                response.readEntity(String.class));
+    }
+
+    @Test
+    public void emptyStringQueryParamReturnsListWithNullInside() {
+        Response response = target("/uuid")
+            .queryParam("list", "ec0cf621-d744-4a1c-b1d8-4b8a44b3dad7", "", "ac0cf621-d744-4a1c-b1d8-4b8a44b3dad7")
+            .request()
+            .get();
+        assertEquals(200, response.getStatus());
+        assertEquals("3: [ec0cf621-d744-4a1c-b1d8-4b8a44b3dad7, null, ac0cf621-d744-4a1c-b1d8-4b8a44b3dad7]",
+                response.readEntity(String.class));
+    }
+
+    @Test
+    public void missingQueryParamReturnsEmptyList() {
+        Response response = target("/uuid")
+            .request()
+            .get();
+        assertEquals(200, response.getStatus());
+        assertEquals("0: []", response.readEntity(String.class));
+    }
+
+    @Test
+    public void filledQueryParamReturnsListWithOneElement() {
+        Response response = target("/uuid")
+            .queryParam("list", "ec0cf621-d744-4a1c-b1d8-4b8a44b3dad7")
+            .request()
+            .get();
+        assertEquals(200, response.getStatus());
+        assertEquals("1: [ec0cf621-d744-4a1c-b1d8-4b8a44b3dad7]", response.readEntity(String.class));
+    }
+
+    @Produces(MediaType.TEXT_PLAIN)
+    @Path("/")
+    public static class TestResource {
+        @GET
+        @Path("/optionalInteger")
+        public String optionalInt(@QueryParam("i") Optional<Integer> i) {
+            if (i == null) {
+                return "null";
+            }
+            return i.map(param -> "i was " + param).orElse("default");
+        }
+
+        @GET
+        @Path("/integer")
+        public String integer(@QueryParam("i") Integer i) {
+            if (i == null) {
+                return "null";
+            }
+            return "i was " + i;
+        }
+
+        @GET
+        @Path("/int")
+        public String primitiveInt(@QueryParam("i") int i) {
+            return "i was " + i;
+        }
+
+        @GET
+        @Path("/uuid")
+        public String uuid(@QueryParam("list") List<UUID> list) {
+            return list.size() + ": " + list.toString();
+        }
+
+        @GET
+        @Path("/string")
+        public String string(@QueryParam("s") String s) {
+            if (s == null) {
+                return "null";
+            }
+            return "s was " + s;
+        }
+
+    }
+}

tests/e2e-server/src/test/java/org/glassfish/jersey/tests/e2e/server/OptionalParamConverterTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 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
@@ -156,8 +156,8 @@ public void fromOptionalDate() {
         Response invalid = target("/OptionalResource/fromDate").queryParam(PARAM_NAME, "invalid").request().get();
         assertEquals(200, missing.getStatus());
         assertEquals(new Date(1609459200000L), missing.readEntity(Date.class));
-        assertEquals(404, empty.getStatus());
-        assertFalse(empty.hasEntity());
+        assertEquals(200, empty.getStatus());
+        assertEquals(new Date(1609459200000L), empty.readEntity(Date.class));
         assertEquals(200, notEmpty.getStatus());
         assertEquals(new Date(1619870400000L), notEmpty.readEntity(Date.class));
         assertEquals(404, invalid.getStatus());
@@ -173,8 +173,8 @@ public void fromOptionalInstant() {
         Response invalid = target("/OptionalResource/fromInstant").queryParam(PARAM_NAME, "invalid").request().get();
         assertEquals(200, missing.getStatus());
         assertEquals("2021-01-01T00:00:00Z", missing.readEntity(String.class));
-        assertEquals(404, empty.getStatus());
-        assertFalse(empty.hasEntity());
+        assertEquals(200, empty.getStatus());
+        assertEquals("2021-01-01T00:00:00Z", empty.readEntity(String.class));
         assertEquals(200, notEmpty.getStatus());
         assertEquals("2021-05-01T12:00:00Z", notEmpty.readEntity(String.class));
         assertEquals(404, invalid.getStatus());

tests/integration/jersey-2612/src/main/java/org/glassfish/jersey/tests/integration/jersey2612/OptionalParamConverterProvider.java

@@ -63,13 +63,16 @@ public String toString(final T value) throws IllegalArgumentException {
         final Set<ParamConverterProvider> converterProviders =
                 Providers.getProviders(injectionManager, ParamConverterProvider.class);
         for (ParamConverterProvider provider : converterProviders) {
-            @SuppressWarnings("unchecked")
             final ParamConverter<?> converter = provider.getConverter(ctp.rawClass(), ctp.type(), annotations);
             if (converter != null) {
                 return new ParamConverter<T>() {
                     @Override
                     public T fromString(final String value) {
-                        return rawType.cast(Optional.ofNullable(value).map(o -> converter.fromString(value)));
+                        if (value.isEmpty()) {
+                            return rawType.cast(Optional.empty());
+                        } else {
+                            return rawType.cast(Optional.ofNullable(value).map(o -> converter.fromString(value)));
+                        }
                     }
 
                     @Override