logic: fix update of Java indexer to new version of Java dependencies

* reapplied previous reverts
* added cache for TypeSolvers in Java code

src/lib_java/data/parser/java/JavaEnvironment.cpp

@@ -10,6 +10,18 @@ JavaEnvironment::~JavaEnvironment()
 	JavaEnvironmentFactory::getInstance()->unregisterEnvironment();
 }
 
+bool JavaEnvironment::callStaticVoidMethod(std::string className, std::string methodName)
+{
+	jclass javaClass = getJavaClass(className);
+	jmethodID javaMethodId = getJavaStaticMethod(javaClass, methodName, "()V");
+	if(javaMethodId != nullptr)
+	{
+		m_env->CallStaticVoidMethod(javaClass, javaMethodId);
+		return true;
+	}
+	return false;
+}
+
 bool JavaEnvironment::callStaticVoidMethod(std::string className, std::string methodName, int arg1, std::string arg2, std::string arg3, std::string arg4, int arg5)
 {
 	jclass javaClass = getJavaClass(className);

src/lib_java/data/parser/java/JavaEnvironment.h

@@ -32,6 +32,7 @@ public:
 	};
 
 	~JavaEnvironment();
+	bool callStaticVoidMethod(std::string className, std::string methodName);
 	bool callStaticVoidMethod(std::string className, std::string methodName, int arg1, std::string arg2, std::string arg3, std::string arg4, int arg5);
 	bool callStaticMethod(std::string className, std::string methodName, std::string& ret, std::string arg1);
 

src/lib_java/data/parser/java/JavaEnvironmentFactory.cpp

@@ -28,7 +28,6 @@ void JavaEnvironmentFactory::createInstance(std::string classPath, std::string&
 	}
 
 	std::function<jint (JavaVM**, void**, void*)> createInstanceFunction;
-
 	const FilePath javaPath(ApplicationSettings::getInstance()->getJavaPath());
 	createInstanceFunction = utility::loadFunctionFromLibrary<jint, JavaVM**, void**, void*>(
 		javaPath,

src/lib_java/data/parser/java/JavaParser.cpp

@@ -26,7 +26,7 @@ std::string JavaParser::prepareJavaEnvironment()
 		const std::string separator = ":";
 #endif
 		JavaEnvironmentFactory::createInstance(
-			ResourcePaths::getJavaPath().str() + "guava-18.0.jar" + separator +
+			ResourcePaths::getJavaPath().str() + "guava-21.0.jar" + separator +
 			ResourcePaths::getJavaPath().str() + "java-indexer.jar" + separator +
 			ResourcePaths::getJavaPath().str() + "javaparser-core.jar" + separator +
 			ResourcePaths::getJavaPath().str() + "javaslang-2.0.3.jar" + separator +
@@ -41,6 +41,22 @@ std::string JavaParser::prepareJavaEnvironment()
 	return errorString;
 }
 
+void JavaParser::clearCaches()
+{
+	std::shared_ptr<JavaEnvironmentFactory> factory = JavaEnvironmentFactory::getInstance();
+	if (factory)
+	{
+		std::shared_ptr<JavaEnvironment> environment = factory->createEnvironment();
+		if (environment)
+		{
+			environment->callStaticVoidMethod(
+				"com/sourcetrail/JavaIndexer",
+				"clearCaches"
+			);
+		}
+	}
+}
+
 JavaParser::JavaParser(std::shared_ptr<ParserClient> client, std::shared_ptr<FileRegister> fileRegister)
 	: Parser(client)
 	, m_id(s_nextParserId++)

src/lib_java/data/parser/java/JavaParser.h

@@ -33,6 +33,7 @@ class JavaParser: public Parser
 public:
 	// returns: error message
 	static std::string prepareJavaEnvironment();
+	static void clearCaches();
 
 	JavaParser(std::shared_ptr<ParserClient> client, std::shared_ptr<FileRegister> fileRegister);
 	~JavaParser();