Fallback to current class if loading a Jsonp provider using ServiceLo…

…ader fails (#173)

config/forbidden-apis.txt

@@ -0,0 +1,3 @@
+@defaultMessage JsonProvider.provider() should not be used directly. Use JsonpUtils#provider() instead.
+jakarta.json.spi.JsonProvider#provider()
+

java-client/build.gradle.kts

@@ -27,6 +27,7 @@ plugins {
     checkstyle
     `maven-publish`
     id("com.github.jk1.dependency-license-report") version "1.17"
+    id("de.thetaphi.forbiddenapis") version "3.2"
 }
 
 java {
@@ -37,6 +38,15 @@ java {
     withSourcesJar()
 }
 
+forbiddenApis {
+    signaturesFiles = files(File(rootProject.projectDir, "config/forbidden-apis.txt"))
+    suppressAnnotations = setOf("co.elastic.clients.util.AllowForbiddenApis")
+}
+
+tasks.forbiddenApisMain {
+    bundledSignatures = setOf("jdk-system-out")
+}
+
 tasks.getByName<ProcessResources>("processResources") {
     // Only process main source-set resources (test files are large)
     expand(
@@ -193,7 +203,10 @@ dependencies {
 
     // EPL-2.0 OR BSD-3-Clause
     // https://eclipse-ee4j.github.io/yasson/
-    testImplementation("org.eclipse", "yasson", "2.0.2")
+    testImplementation("org.eclipse", "yasson", "2.0.2") {
+        // Exclude Glassfish as we use Parsson (basically Glassfish renamed in the Jakarta namespace).
+        exclude(group = "org.glassfish", module = "jakarta.json")
+    }
 
     // EPL-1.0
     // https://junit.org/junit4/

java-client/src/main/java/co/elastic/clients/json/JsonpUtils.java

@@ -19,10 +19,13 @@
 
 package co.elastic.clients.json;
 
+import co.elastic.clients.util.AllowForbiddenApis;
 import co.elastic.clients.util.ObjectBuilder;
+import jakarta.json.JsonException;
 import jakarta.json.JsonObject;
 import jakarta.json.JsonString;
 import jakarta.json.JsonValue;
+import jakarta.json.spi.JsonProvider;
 import jakarta.json.stream.JsonGenerator;
 import jakarta.json.stream.JsonParser;
 import jakarta.json.stream.JsonParser.Event;
@@ -32,10 +35,42 @@
 import java.io.StringReader;
 import java.util.AbstractMap;
 import java.util.Map;
+import java.util.ServiceLoader;
 import java.util.stream.Collectors;
 
 public class JsonpUtils {
 
+    /**
+     * Get a <code>JsonProvider</code> instance. This method first calls the standard `JsonProvider.provider()` that is based on
+     * the current thread's context classloader, and in case of failure tries to find a provider in other classloaders.
+     */
+    @AllowForbiddenApis("Implementation of the JsonProvider lookup")
+    public static JsonProvider provider() {
+        RuntimeException exception;
+        try {
+            return JsonProvider.provider();
+        } catch(RuntimeException re) {
+            exception = re;
+        }
+
+        // Not found from the thread's context classloader. Try from our own classloader which should be a descendant of an app-server
+        // classloader if any, and if it still fails try from the SPI class which hopefully will be close to the implementation.
+
+        try {
+            return ServiceLoader.load(JsonProvider.class, JsonpUtils.class.getClassLoader()).iterator().next();
+        } catch(Exception e) {
+            // ignore
+        }
+
+        try {
+            return ServiceLoader.load(JsonProvider.class, JsonProvider.class.getClassLoader()).iterator().next();
+        } catch(Exception e) {
+            // ignore
+        }
+
+        throw new JsonException("Unable to get a JsonProvider. Check your classpath or thread context classloader.", exception);
+    }
+
     /**
      * Advances the parser to the next event and checks that this even is the expected one.
      *

java-client/src/main/java/co/elastic/clients/json/jackson/JacksonJsonProvider.java

@@ -19,6 +19,7 @@
 
 package co.elastic.clients.json.jackson;
 
+import co.elastic.clients.json.JsonpUtils;
 import com.fasterxml.jackson.core.JsonFactory;
 import jakarta.json.JsonArray;
 import jakarta.json.JsonArrayBuilder;
@@ -133,15 +134,15 @@ public JsonParser createParser(InputStream in, Charset charset) {
          */
         @Override
         public JsonParser createParser(JsonObject obj) {
-            return JsonProvider.provider().createParserFactory(null).createParser(obj);
+            return JsonpUtils.provider().createParserFactory(null).createParser(obj);
         }
 
         /**
          * Not implemented.
          */
         @Override
         public JsonParser createParser(JsonArray array) {
-            return JsonProvider.provider().createParserFactory(null).createParser(array);
+            return JsonpUtils.provider().createParserFactory(null).createParser(array);
         }
 
         /**

java-client/src/main/java/co/elastic/clients/json/jackson/JsonValueParser.java

@@ -19,6 +19,7 @@
 
 package co.elastic.clients.json.jackson;
 
+import co.elastic.clients.json.JsonpUtils;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonToken;
 import jakarta.json.JsonArray;
@@ -36,7 +37,7 @@
  * object (e.g. START_OBJECT, VALUE_NUMBER, etc).
  */
 class JsonValueParser {
-    private final JsonProvider provider = JsonProvider.provider();
+    private final JsonProvider provider = JsonpUtils.provider();
 
     public JsonObject parseObject(JsonParser parser) throws IOException {
 

java-client/src/main/java/co/elastic/clients/json/jsonb/JsonbJsonpMapper.java

@@ -24,6 +24,7 @@
 import co.elastic.clients.json.JsonpMapper;
 import co.elastic.clients.json.JsonpMapperBase;
 import co.elastic.clients.json.JsonpSerializable;
+import co.elastic.clients.json.JsonpUtils;
 import jakarta.json.bind.Jsonb;
 import jakarta.json.bind.spi.JsonbProvider;
 import jakarta.json.spi.JsonProvider;
@@ -50,7 +51,7 @@ public JsonbJsonpMapper(JsonProvider jsonProvider, JsonbProvider jsonbProvider)
     }
 
     public JsonbJsonpMapper() {
-        this(JsonProvider.provider(), JsonbProvider.provider());
+        this(JsonpUtils.provider(), JsonbProvider.provider());
     }
 
     @Override

java-client/src/main/java/co/elastic/clients/util/AllowForbiddenApis.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package co.elastic.clients.util;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to allow usage of forbidden APIs inside a whole class, a method, or a field.
+ */
+@Retention(RetentionPolicy.CLASS)
+@Target({ ElementType.CONSTRUCTOR, ElementType.FIELD, ElementType.METHOD, ElementType.TYPE })
+public @interface AllowForbiddenApis {
+    /**
+     * The reason for allowing forbidden APIs
+     */
+    String value();
+}

java-client/src/test/java/co/elastic/clients/elasticsearch/experiments/ParsingTests.java

@@ -20,6 +20,7 @@
 package co.elastic.clients.elasticsearch.experiments;
 
 import co.elastic.clients.elasticsearch.experiments.api.FooRequest;
+import co.elastic.clients.json.JsonpUtils;
 import co.elastic.clients.json.jsonb.JsonbJsonpMapper;
 import jakarta.json.spi.JsonProvider;
 import jakarta.json.stream.JsonGenerator;
@@ -50,7 +51,7 @@ public void testFoo() throws Exception {
           )
           .build();
 
-      JsonProvider provider = JsonProvider.provider();
+      JsonProvider provider = JsonpUtils.provider();
       JsonGenerator generator = provider.createGenerator(baos);
       foo.serialize(generator, new JsonbJsonpMapper());
 

java-client/src/test/java/co/elastic/clients/elasticsearch/experiments/containers/SomeUnionTest.java

@@ -20,6 +20,7 @@
 package co.elastic.clients.elasticsearch.experiments.containers;
 
 import co.elastic.clients.elasticsearch.model.ModelTestCase;
+import co.elastic.clients.json.JsonpUtils;
 import co.elastic.clients.json.jsonb.JsonbJsonpMapper;
 import jakarta.json.spi.JsonProvider;
 import jakarta.json.stream.JsonGenerator;
@@ -55,7 +56,7 @@ public void testDeserialization() {
     public void testSerialization() {
 
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        JsonProvider provider = JsonProvider.provider();
+        JsonProvider provider = JsonpUtils.provider();
         JsonGenerator generator = provider.createGenerator(baos);
 
         su.serialize(generator, new JsonbJsonpMapper());
@@ -71,7 +72,7 @@ public void testSerialization() {
     public void testMissingVariantDeserialization() {
         String json = "{}";
 
-        JsonProvider provider = JsonProvider.provider();
+        JsonProvider provider = JsonpUtils.provider();
         JsonParser parser = provider.createParser(new StringReader(json));
 
         JsonParsingException e = assertThrows(JsonParsingException.class, () -> {

java-client/src/test/java/co/elastic/clients/elasticsearch/experiments/inheritance/InheritanceTest.java

@@ -21,6 +21,7 @@
 
 import co.elastic.clients.elasticsearch.experiments.inheritance.child.ChildClass;
 import co.elastic.clients.elasticsearch.experiments.inheritance.final_.FinalClass;
+import co.elastic.clients.json.JsonpUtils;
 import co.elastic.clients.json.jsonb.JsonbJsonpMapper;
 import jakarta.json.spi.JsonProvider;
 import jakarta.json.stream.JsonGenerator;
@@ -37,7 +38,7 @@ public class InheritanceTest extends Assert {
     public void testSerialization() {
 
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        JsonProvider provider = JsonProvider.provider();
+        JsonProvider provider = JsonpUtils.provider();
 
         FinalClass fc = new FinalClass.Builder()
             // Start fields from the top of the hierarchy to test setter return values
@@ -73,7 +74,7 @@ public void testSerialization() {
 
     @Test
     public void testDeserialization() {
-        JsonProvider provider = JsonProvider.provider();
+        JsonProvider provider = JsonpUtils.provider();
 
         JsonParser parser = provider.createParser(new StringReader(
             "{\"baseField\":\"baseValue\",\"childField\":\"childValue\",\"finalField\":\"finalValue\"}"));

java-client/src/test/java/co/elastic/clients/elasticsearch/json/JsonpUtilsTest.java

@@ -0,0 +1,63 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package co.elastic.clients.elasticsearch.json;
+
+import co.elastic.clients.json.JsonpUtils;
+import co.elastic.clients.util.AllowForbiddenApis;
+import jakarta.json.JsonException;
+import jakarta.json.spi.JsonProvider;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.net.URL;
+import java.util.Collections;
+import java.util.Enumeration;
+
+public class JsonpUtilsTest extends Assert {
+
+    @Test
+    @AllowForbiddenApis("Testing JsonpUtil.provider()")
+    public void testProviderLoading() {
+        // See https://github.com/elastic/elasticsearch-java/issues/163
+
+        // Create an empty non-delegating classloader and set it as the context classloader. It simulates a
+        // plugin system that doesn't set the context classloader to the plugins classloader.
+        ClassLoader emptyLoader = new ClassLoader() {
+            @Override
+            public Enumeration<URL> getResources(String name) {
+                return Collections.emptyEnumeration();
+            }
+        };
+
+        ClassLoader savedLoader = Thread.currentThread().getContextClassLoader();
+        try {
+            Thread.currentThread().setContextClassLoader(emptyLoader);
+
+            assertThrows(JsonException.class, () -> {
+                assertNotNull(JsonProvider.provider());
+            });
+
+            assertNotNull(JsonpUtils.provider());
+
+        } finally {
+            Thread.currentThread().setContextClassLoader(savedLoader);
+        }
+    }
+}