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Spring doesn't track changes on files stored in "./resources/" folder

I'm new to Spring Boot, so I'm not sure about how to store/manipulate files (use persistance within spring). Use case: Store list of films (title, director...) on a JSON file stored on API server with persistance instead of using a DB.
I have a favorites.json at src/main/resources. This file is updated when request arrives as I said. Code here: GitHub Repo
A kind person has left in the comments what is probably the problem. Changes files in classpath won't work. I still struggling how store data in JSON without a database.
Problem I'm facing:
Files are updated correctly at POST request via OutputStream, but it seems like favorites.json is treated as a static resource, so any update will be ignored until API starts again (I have tried restarting the api when the file is updated, see this but it doesn't change anything. It's still needed to stop and start manually, bash script may help, but I prefer another solution if better-possible.
Maybe I'm looking for a file-based repository, place this file in a specific project path where spring detect updates.
I think I'm skipping some important concepts of spring behaviour.
Here POST Resource
#CrossOrigin(origins = "http://localhost:3000")
#PostMapping(path = TaskLinks.FAVORITES, consumes = "application/json", produces = "application/json")
#ResponseBody
public String updateFavs(#RequestBody List<Show> newFavorites) {
showService.updateFavorites(newFavorites);
return "All right";
}
Methods that modify the file:
public boolean updateFavorites(List<Show> newFavorites) {
if (newFavorites == null)
return false;
setNewFavorites(newFavorites);
return true;
}
private void setNewFavorites(List<Show> newFavorites) {
Gson gson = new Gson();
try {
FileWriter fileW = new FileWriter(FAVORITES_PATH);
String strNewFavs = gson.toJson(newFavorites);
fileW.write(strNewFavs);
fileW.close(); // auto flush
} catch (JsonIOException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

If someone needs to use spring boot persistence system, I will let here what I've found.
The unique solution that I've found to use file persistance on spring-boot (API) is to hard-reload the whole API, which I think is not a clean thing.
So I ended up storing the JSON file on mysql.
Maybe spring have specific tools that I've omitted, but I don't have time to check right now.
The closest approach I got was accessing system temporary file, which is correctly updated because it's allocated outside the application.
I didn't get access to files outside the application other than temporary ones.
Now I'm working with NodeJS express and implemented a png delivery API. I don't really know how I would've done it with spring at all, but there's probably a file focused database or something that may work fine with spring. If I have to face this situation, I will upload the solution that I find most favorable. At the moment express works fine.

Tomcat 7 - Get the application name during runtime without login via java-agent/aspectj

I'm trying to get a list of all deployed applications, and specifically the name of the application mapped to tomcat root.
I want to be able to do it during runtime, using a java agent that collects information on the tomcat server.
I tried using this code sample:
private Iterable<String> collectAllDeployedApps() {
try {
final Set<String> result = new HashSet<>();
final Set<ObjectName> instances = findServer()
.queryNames(new ObjectName("Tomcat:j2eeType=WebModule,*"), null);
for (ObjectName each : instances) {
result.add(substringAfterLast(each.getKeyProperty("name"), "/")); //it will be in format like //localhost/appname
}
return result;
} catch (MalformedObjectNameException e) {
//handle
}
}
taken from a similar question but since I'm not logged into the manager app, I don't have the right permissions, so I get an empty list.
What I actually want - I have a java agent (based on aspectJ), and I'd like during runtime/deployment time etc. to be able to get the list of all deployed apps without actually logging in to the manager myself.
How can I do this? I don't mind instrumenting tomcat's deployment code (which doesn't require any login from my side as I'm already instrumenting the code), but I'm not sure which function to instrument.
Thanks,
Lin

The question consists of 2 parts:
Get a list of all deployed applications - After reviewing Tomcat's API, I found several relevant deployment code parts which can be instrumented:
WarWatcher.java (allows to detect changes), and we can also see the apps from - UserConfig.java which is called on startup (instrumentation can be done on setDirectory name etc.), and of course HostConfig.java that is called on stratup:
protected void org.apache.catalina.startup.HostConfig.deployWARs(java.io.File, java.lang.String[])
protected void org.apache.catalina.startup.HostConfig.deployApps()
protected void org.apache.catalina.startup.HostConfig.deployWAR(org.apache.catalina.util.ContextName, java.io.File)
In addition - you can check the argument for:
protected boolean org.apache.catalina.startup.HostConfig.deploymentExists(java.lang.String)
It includes the war/folder name (which usually means the application name+-).
Get the root application name - This can be done by using ServletContext.getRealPath() - It returns the folder name, from which the war name can be extracted (and can be used, in my case at least as the app name).

Java InvocationTargetException

I have used EMC Documentum Foundation Classes to perform some actions in documentum repository. The code was working fine. I exported the project as a runnable JAR and then tried to run it. However I got following error and I am not able to understand it.
And here is the code for DocMovementHandler.getSession()
Actually this is no new code but regular code for obtaining documentum session
public IDfSession getSession(String userName, String password)
{
DfClientX clientx = null;
IDfClient client = null;
IDfSession session = null;
try {
// create a client object using a factory method in DfClientX
clientx = new DfClientX();
client = clientx.getLocalClient(); //takes time
// call a factory method to create the session manager
IDfSessionManager sessionMgr = client.newSessionManager();
// create an IDfLoginInfo object and set its fields
IDfLoginInfo loginInfo = clientx.getLoginInfo();
loginInfo.setUser(userName);
loginInfo.setPassword(password);
// set single identity for all docbases
sessionMgr.setIdentity("xyz_repo", loginInfo);
session = sessionMgr.getSession("xyz_repo"); //takes time
//sessionMgr.beginTransaction();
System.out.println("Session obtaied.");
}
catch (DfServiceException dse)
{
DfLogger.debug(this, "Error while beginning transaction. ", null, dse);
dse.printStackTrace();
}
catch (Exception e)
{
DfLogger.debug(this, "Error while creating a new session. ", null, e);
e.printStackTrace();
}
return session;
}
And that line 38 is client = clientx.getLocalClient();

InvocationTargetException is a wrapper. It says, "an exception occurred behind this reflection call", and you use getCause() to get at the inner exception.
The stack trace contains the inner exception. It's an ExceptionInInitializerError. That's another wrapper. It says, "whatever you did caused a new class to be loaded, and that class's static initializer threw an exception".
The final exception in this chain is the NullPointerException. That's the one you need to solve. Which means you need to debug this com.documentum thing. As the comments pointed out, that's not going to be easy.

Here is the most likely problem:
The static initializer in one of the classes whose names you have struck is adding an entry with either a null key or a null value to a Hashtable, which does not allow null keys or values.
It is using the Hashtable as a place to store a bunch of persistent properties and all that, and my guess is that the value for one of the entries was the null (which is a perfectly reasonable way to indicate that some feature is unavailable or something like that).
The now deprecated Hashtable needs to be replaced with the more modern HashMap.
If it is a library, that you can't just modify, you should replace the whole library with an updated version.

Here are some clues may be helpful.
The NullPointerException is thrown by Hashtable#put, and this is normally because either the key or the value is null.
Hashtable#put is called by PreferenceManager.readPersistenceProperties, so most likely it's because something is missing in a properties file so the value is null.
This NPE caused the DfClient class could not be loaded.

DfPreferences is the class loading the DFC configuration file dfc.properties. There must be something wrong with it.

Ohkay I did not pin pointed the root cause, but found the solution that will definitely work everytime.
EMC provides a flavor of Eclipse called Documentum Composer to work with Documentum Projects. Since Eclipse variation we can create other types of projects like normal Java project, dynamic web project, web services in this. So I recreated my project in Documetnum Composer and exported it as JAR and whoaaaa it worked.
I tried this many times and this worked all time.
Some points to note:
You have to replace dfc.properties file in Composer installation folder with one in Content Server
The Export to JAR wizard in Composer is a bit different than one in Eclipse

This is usually caused by dfc.properties being incorrect.
Preferences are stored on the global registry repository and the connection details should be specified in dfc.properties. If not, this (or a similar error can occur).
Also, always try to clear cache and use the correct version of the dfc jar's (v6.7 content server requires 6.7 jars, etc...).

Any Java API in Azure to get existing ServiceBusContract?

I am using the tutorial here for pushing data and consuming, data from Azure Service Bus. When I run the example the second time, I get back an error PUT https://asbtest.servicebus.windows.net/TestQueue?api-version=2012-08 returned a response status of 409 Conflict, which is way of saying you have already a configuration with that name, so do not create it another time. Most probably, this is the guilty code
Configuration config =
ServiceBusConfiguration.configureWithWrapAuthentication(
"HowToSample",
"your_service_bus_owner",
"your_service_bus_key",
".servicebus.windows.net",
"-sb.accesscontrol.windows.net/WRAPv0.9");
ServiceBusContract service = ServiceBusService.create(config);
QueueInfo queueInfo = new QueueInfo("TestQueue");
That is recalling create() is causing the problem, I would guess. But all methods in com.microsoft.windowsazure.services.serviceBus.ServiceBusService from http://dl.windowsazure.com/javadoc/ are only create, and I am unable to find a method like
ServiceBusContract service = A_class_that_finds_existing_bus_contract.find(config);
Am I thinking the wrong way, or is there another way out. Any pointers are appreciated.
EDIT:
I realized my code example for what I was asking was config, not service bus contract. Updated it, to reflect so.

Turns out I was wrong. The create() function in ServiceBusService does not throw any exception, as I gathered from Javadocs. Also, you can create the service bus contracts multiple times, as it being only a connection. The exception arises, when you attempt to create a queue with a name that already exists. That is this line.
String path = "TestQueue";
QueueInfo queueInfo = new QueueInfo(path);
To overcome this, you can go this way.
import com.microsoft.windowsazure.services.serviceBus.Util;
...
...
Iterable<QueueInfo> iqnf = Util.iterateQueues(service);
boolean queue_created = false;
for( QueueInfo qi : iqnf )
{
if( path.toLowerCase().equals( qi.getPath() ))
{
System.out.println(" Queue already exists. Do not create one.");
queue_created = true;
}
}
if ( !queue_created ) {
service.createQueue(queueInfo);
}
Hope, this helps anybody who may be stuck on create conflicts for queue on Azure.
EDIT: Even after I got the path code, my code refused to work. Turns out there is another caveat. Azure makes all queue names in lower case. I have edited the code to use toLower() for this work around.

I upvoted Soham's Question and Answer. I did not know about lowercase though I have not verified it. It did confirm the problem I am having right now as well.
The way #Soham has addressed it is good but not good for large ServicebUs where we may have tons of Queues it's added overhead to iterate it. The only way is to catch the ServiceException which is very generic and ignore that Exception.
Example:
QueueInfo queueInfo = new QueueInfo(queName);
try {
CreateQueueResult qr = service.createQueue(queueInfo);
} catch (ServiceException e) {
//Silently ignore for now.
}
The right way would be for the Azure library to extend the ServiceException and throw "ConcflictException" for e.g. which is present in httpStatusCode of ServiceException but unfortunately it's set to Private.
Since it is not We would have to extend the ServiceException and override the httpStatusCode setter.
Again, not the best way but the library can improve if we list as feedback on their Github issues.
Note: ServiceBus is still in preview phase.

Java Jinput: rescan / reload controllers

I am using java jinput library to read data from joypad, and I have trouble reloading Controllers, I use this to load them:
public Controller[] findStickControllers() {
ControllerEnvironment ce =
ControllerEnvironment.getDefaultEnvironment();
Controller[] cs = ce.getControllers();
System.out.println(cs.length); //test
ArrayList<Controller> sel = new ArrayList<>();
for (Controller c: cs) {
if(c.getType() == Type.STICK) {
sel.add(c);
}
}
return sel.toArray(new Controller[]{});
}
This works fine, but if I disconnect my controller, calling this will find it again, and vice versa (connecting it after the first check will not find it at all).
I have tried to put sleep before the fist lookup, with these results:
Controllers are acctually scanned when this method is called first time (not at start of the program)
When called again, this always returns same controllers as it returned for the first time.
First call will also write warning bellow
Even when controller is connected (and works), then disconnected (it will still find it though) and reconnected, it will not work
Warning from point 3: (didn't format well in the list)
WARNING: Found unknown Windows version: Windows 8
Attempting to use default windows plug-in.
Loading: net.java.games.input.DirectAndRawInputEnvironmentPlugin
I am using Win 8, and had same problem on Win 7. I had also tried this with mouse, same results.
How can I acctually reload controllers for the 2nd, 3rd, and so on time?

I encountered the same problem. The reason is that the actual hardware scan happens only once for each DefaultControllerEnvironment object. Since the only accessible instantiation is a singleton, it never does another scan.
A simple way to force a hardware scan is to create a new object, but neither the class nor the constructor are public. You can however work around this limitation by calling the constructor via reflection.
Rescan
private static ControllerEnvironment createDefaultEnvironment() throws ReflectiveOperationException {
// Find constructor (class is package private, so we can't access it directly)
Constructor<ControllerEnvironment> constructor = (Constructor<ControllerEnvironment>)
Class.forName("net.java.games.input.DefaultControllerEnvironment").getDeclaredConstructors()[0];
// Constructor is package private, so we have to deactivate access control checks
constructor.setAccessible(true);
// Create object with default constructor
return constructor.newInstance();
}
Usage
// Be aware that creating a new environment is fairly expensive
Controller[] controllers = createDefaultEnvironment().getControllers();
Remove Windows 8 Warnings
/**
* Fix windows 8 warnings by defining a working plugin
*/
static {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
String os = System.getProperty("os.name", "").trim();
if (os.startsWith("Windows 8")) { // 8, 8.1 etc.
// disable default plugin lookup
System.setProperty("jinput.useDefaultPlugin", "false");
// set to same as windows 7 (tested for windows 8 and 8.1)
System.setProperty("net.java.games.input.plugins", "net.java.games.input.DirectAndRawInputEnvironmentPlugin");
}
return null;
}
});
}

If you use the accepted answer, you might want to consider killing the thread that was spawned by the previous environment before setting a new one because it won't be cleaned up otherwise. You can do so by calling something like:
final Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
for (final Thread thread : threadSet) {
final String name = thread.getClass().getName();
if (name.equals("net.java.games.input.RawInputEventQueue$QueueThread")) {
thread.interrupt();
try {
thread.join();
} catch (final InterruptedException e) {
thread.interrupt();
}
}
}

The warning is because the last time I updated that code windows 7 wasn't even out IIRC, I'll update it.
The controller reload is a feature that has been requested a number of times, but no-one deems it important enough to spend any time implementing it. If you submit a patch I'll take a look and see about committing it. Until someone finds it important enough to spend the time to write it, it's just a missing feature.

I had the same problem before.
I add the rescanning feature (for Windows back-end only) and post the patch on Java gaming forum but no ones seem interested in to integrate it.
So if you need it, apply my patch from here: http://www.java-gaming.org/topics/rescan-controllers/24782/msg/224604/view.html#msg224604