Add test for custom class loader.

Author: rhubner

java/CMakeLists.txt

@@ -340,6 +340,7 @@ set(JAVA_TEST_CLASSES
   src/test/java/org/rocksdb/DefaultEnvTest.java
   src/test/java/org/rocksdb/DirectSliceTest.java
   src/test/java/org/rocksdb/EnvOptionsTest.java
+  src/test/java/org/rocksdb/EventListenerClassloaderTest.java
   src/test/java/org/rocksdb/EventListenerTest.java
   src/test/java/org/rocksdb/FilterTest.java
   src/test/java/org/rocksdb/FlushOptionsTest.java
@@ -886,6 +887,25 @@ add_custom_target(rocksdbjava ALL
 
 enable_testing()
 get_target_property(ROCKSDBJNI_CLASSES_TEST_JAR_FILE rocksdbjni_test_classes JAR_FILE)
+get_target_property(ROCKSDBJNI_CLASSES_JAR_FILE rocksdbjni_classes JAR_FILE)
+get_target_property(ROCKSDBJNI_CLASSES_TEST_DIR rocksdbjni_test_classes CLASSDIR)
+
+
+file(MAKE_DIRECTORY ${PROJECT_BINARY_DIR}/java/cl-test/org/rocksdb)
+add_custom_target(cltest-before
+        COMMAND ${CMAKE_COMMAND} -E copy
+        ${ROCKSDBJNI_CLASSES_TEST_DIR}/org/rocksdb/EventListenerClassloaderTest.class
+        ${PROJECT_BINARY_DIR}/java/cl-test/org/rocksdb/EventListenerClassloaderTest.class
+        DEPENDS rocksdbjava
+)
+
+add_test(
+        NAME cltest
+        COMMAND ${Java_JAVA_EXECUTABLE} ${JVMARGS} -ea -Xcheck:jni -Drocks-jar=${ROCKSDBJNI_CLASSES_JAR_FILE} -classpath ${JAVA_RUN_TESTCLASSPATH}:${PROJECT_BINARY_DIR}/java/cl-test org.junit.runner.JUnitCore org.rocksdb.EventListenerClassloaderTest
+)
+
+set_tests_properties(cltest PROPERTIES DEPENDS cltest-before)
+
 foreach (CLAZZ ${JAVA_TEST_RUNNING_CLASSES})
   if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
     add_test(

java/rocksjni/testable_event_listener.cc

@@ -6,6 +6,7 @@
 #include <cstdint>
 #include <iostream>
 #include <utility>
+#include <thread>
 
 #include "include/org_rocksdb_test_TestableEventListener.h"
 #include "rocksdb/listener.h"
@@ -72,6 +73,17 @@ static TableProperties newTablePropertiesForTest() {
   return table_properties;
 }
 
+/*
+ * Class:     org_rocksdb_test_TestableEventListener
+ * Method:    invokeAllCallbacksInThread
+ * Signature: (J)V
+ */
+JNIEXPORT void JNICALL Java_org_rocksdb_test_TestableEventListener_invokeAllCallbacksInThread
+    (JNIEnv *, jclass, jlong jhandle) {
+  std::thread t1 = std::thread(Java_org_rocksdb_test_TestableEventListener_invokeAllCallbacks, nullptr, nullptr, jhandle);
+  t1.join();
+}
+
 /*
  * Class:     org_rocksdb_test_TestableEventListener
  * Method:    invokeAllCallbacks

java/src/test/java/org/rocksdb/EventListenerClassloaderTest.java

@@ -0,0 +1,55 @@
+package org.rocksdb;
+
+
+import org.junit.Test;
+
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
+
+
+
+/**
+ * Only this class can be on default classpath.
+ * It loads rocksDB code with custom classloader and then test that all
+ * event data for event listener can be instantiated.
+ */
+public class EventListenerClassloaderTest {
+
+
+    @Test
+    public void testCallback() throws Exception {
+
+        try {
+            this.getClass().getClassLoader().loadClass("org.rocksdb.RocksDB");
+            fail("It looks like RocksDB is on classpath. This test must load RocksDB via custom classLoader" +
+                    " to verify callback cache all class instances.");
+        }catch (ClassNotFoundException e) {
+            ;
+        }
+
+        String jarPath = System.getProperty("rocks-jar");
+        assertThat(jarPath).isNotNull().as("Java property 'rocks-jar' was not setup properly");
+
+        Path classesDir = Paths.get(jarPath);
+        ClassLoader cl = new URLClassLoader(new URL[]{
+                classesDir.toAbsolutePath().toUri().toURL()
+        });
+
+        Class rocksDBclazz = cl.loadClass("org.rocksdb.RocksDB");
+        Method loadLibrary = rocksDBclazz.getMethod("loadLibrary");
+        loadLibrary.invoke(null);
+
+        Class testableEventListenerClazz = cl.loadClass("org.rocksdb.test.TestableEventListener");
+        Method invokeAllCallbacksInThread = testableEventListenerClazz.getMethod("invokeAllCallbacksInThread");
+        Object instance = testableEventListenerClazz.getDeclaredConstructor().newInstance();
+        invokeAllCallbacksInThread.invoke(instance);
+
+
+    }
+}

java/src/test/java/org/rocksdb/test/TestableEventListener.java

@@ -19,5 +19,10 @@ public void invokeAllCallbacks() {
     invokeAllCallbacks(nativeHandle_);
   }
 
+  public void invokeAllCallbacksInThread() {
+    invokeAllCallbacksInThread(nativeHandle_);
+  }
+
   private static native void invokeAllCallbacks(final long handle);
+  private static native void invokeAllCallbacksInThread(final long handle);
 }