+ * These tests are placed in the integration tests module to ensure that the initialization + * is successful when multiple modules are loaded. + *
+ * These tests need to be run in a separate JVM to run with a not initialized JenaSystem. + * This usually is the case when only the test method is directly executed in the IDE. + * For the maven build, we call these test methods from {@link TestJenaSystemWithFreshJVM} + * to ensure that the JVM is fresh. + */ +public class TestJenaSystem { + + /** + * Tests that the first initialization of JenaSystem is successful. + *
+ * For the maven build, we use this method in {@link TestJenaSystemWithFreshJVM#init()} + * to ensure that the JVM is fresh. + */ + @Test + public void init() { + assertDoesNotThrow( + () -> JenaSystem.init()); + } + + /** + * Tests that the first initialization of {@link JenaSystem} is even successful when called in parallel. + *
+ * This code was able to reproduce a deadlock for GitHub issue 2787, + * which is now fixed. + *
+ * The deadlock was observed when {@link JenaSystem} was initialized in parallel with + * {@link ModelFactory#createDefaultModel()} or other classes that use a static initializer calling + * {@link JenaSystem#init}. This test is used to reproduce the deadlock and ensure that it is fixed. + *
+ * For the maven build, we use this method in {@link org.apache.jena.sys.TestJenaSystemWithFreshJVM#initParallel()}
+ * to ensure that the JVM is fresh.
+ */
+ @Test
+ public void initParallel() {
+
+ var pool = Executors.newFixedThreadPool(2);
+ try {
+ var futures = IntStream.range(1, 3)
+ .mapToObj(i -> pool.submit(() -> {
+ if (i % 2 == 0) {
+ ModelFactory.createDefaultModel();
+ } else {
+ JenaSystem.init();
+ }
+
+ return i;
+ }))
+ .toList();
+
+ var intSet = new HashSet
+ * The issue was:
+ * When the static initialization of {@link JenaSystem} was missing in {@link org.apache.jena.rdflink.RDFLinkHTTPBuilder},
+ * the initialization of {@link RDFConnectionFuseki} failed with a {@link java.lang.ExceptionInInitializerError}
+ * caused by a {@link java.lang.NullPointerException}.
+ *
+ * For the maven build, we use this method in {@link TestJenaSystemWithFreshJVM#initRDFConnectionFuseki()}
+ */
+ @Test
+ public void initRDFConnectionFuseki() {
+ try (RDFConnection conn = RDFConnectionFuseki.service("http://localhost:3030/ds").build()) {
+ assertTrue(true);
+ }
+ }
+}
diff --git a/jena-integration-tests/src/test/java/org/apache/jena/sys/TestJenaSystemWithFreshJVM.java b/jena-integration-tests/src/test/java/org/apache/jena/sys/TestJenaSystemWithFreshJVM.java
new file mode 100644
index 00000000000..a73e72b68cc
--- /dev/null
+++ b/jena-integration-tests/src/test/java/org/apache/jena/sys/TestJenaSystemWithFreshJVM.java
@@ -0,0 +1,97 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF 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 org.apache.jena.sys;
+
+import org.apache.jena.rdfconnection.RDFConnectionFuseki;
+import org.junit.Assert;
+import org.junit.Test;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+import org.openjdk.jmh.runner.options.TimeValue;
+import org.openjdk.jmh.runner.options.VerboseMode;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * This test is not a benchmark but a test to ensure that the test methods from {@link TestJenaSystem} are executed
+ * in a fresh JVM.
+ */
+@State(Scope.Benchmark)
+public class TestJenaSystemWithFreshJVM {
+
+ static final TestJenaSystem testJenaSystem = new TestJenaSystem();
+
+ /**
+ * Test that the first initialization of JenaSystem is successful when called in parallel.
+ *
+ * Executes test code of {@link TestJenaSystem#initParallel()}.
+ */
+ @Benchmark
+ public void initParallel() {
+ testJenaSystem.initParallel();
+ }
+
+ /**
+ * Test that the first initialization of JenaSystem is successful.
+ *
+ * Executes test code of {@link TestJenaSystem#init()}.
+ */
+ @Benchmark
+ public void init() {
+ testJenaSystem.init();
+ }
+
+ /**
+ * This test ensures that the initialization of {@link RDFConnectionFuseki} is successful.
+ * It is a regression test for GitHub issue 2787.
+ *
+ * Executes test code of {@link TestJenaSystem#initRDFConnectionFuseki()}.
+ */
+ @Benchmark
+ public void initRDFConnectionFuseki() {
+ testJenaSystem.initRDFConnectionFuseki();
+ }
+
+ /**
+ * This test uses JMH to run the test methods from {@link TestJenaSystem} in a fresh JVM.
+ * This is necessary for maven builds to ensure that the JVM is fresh.
+ */
+ @Test
+ public void initInFreshJVM() throws Exception {
+ var opt = new OptionsBuilder()
+ .include(this.getClass().getName())
+ .mode(Mode.SingleShotTime)
+ .verbosity(VerboseMode.SILENT)
+ .timeUnit(TimeUnit.SECONDS)
+ .warmupTime(TimeValue.NONE)
+ .warmupIterations(0) // we don't need warmup
+ .measurementIterations(1) // we only need one iteration
+ .measurementTime(TimeValue.NONE)
+ .threads(1) // we only need one thread
+ .forks(1) // we only need one fork
+ .shouldFailOnError(true) // this is important to fail the test if the benchmark fails
+ .timeout(TimeValue.seconds(6)) // 6 seconds should be enough, even on slow machines
+ .build();
+ var results = new Runner(opt).run();
+ Assert.assertNotNull(results);
+ }
+}