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Unable to resolve java build / Spring

First Thing to say, I am a relatively inexperienced programmer.
My task is to import a given gradle project into Spring Boot Tool Suite (sts). I have already download springboot cli, java, gradle. & In the past, I was able to run spring perfectly on another project, unfortunately I had to get my hard drive replaced, so I lost a considerable amount of downloads.
Nonetheless, my issue is two-parted. Firstly, my tool suite (ide? It's basically eclipse) does not recognize my project as a a java project, I have tried many options & the only was to fix that portion is to hardcode org.eclipse.core.javabuilder within the buildCommand tag in my .project file, which I don't remember doing for my last project.
Here is the directory tree of the backend folder(don't concern with the frontend)
.
├── build.gradle
├── gradle
│   └── wrapper
│   ├── gradle-wrapper.jar
│   └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── src
├── main
│   ├── java
│   │   └── ca
│   │   └── mcgill
│   │   └── ecse321
│   │   └── eventregistration
│   │   ├── EventRegistrationApplication.java
│   │   ├── controller
│   │   │   ├── ApiError.java
│   │   │   ├── EventRegistrationRestController.java
│   │   │   └── RestExceptionHandler.java
│   │   ├── dao
│   │   │   ├── EventRegistrationRepository.java
│   │   │   ├── EventRepository.java
│   │   │   ├── PersonRepository.java
│   │   │   └── RegistrationRepository.java
│   │   ├── dto
│   │   │   ├── EventDto.java
│   │   │   ├── PersonDto.java
│   │   │   └── RegistrationDto.java
│   │   ├── model
│   │   │   ├── Event.java
│   │   │   ├── Person.java
│   │   │   ├── Registration.java
│   │   │   └── RegistrationManager.java
│   │   └── service
│   │   └── EventRegistrationService.java
│   └── resources
│   └── application.properties
└── test
└── java
└── ca
└── mcgill
└── ecse321
└── eventregistration
└── service
├── event
│   └── TestCinema.java
├── payment
│   ├── TestPaymentWithCreditCard.java
│   ├── TestPaymentWithCreditCardData.java
│   └── TestUtils.java
└── role
├── PromoterRoleTestData.java
└── TestPromoterRole.java
Additionally, Here it my build.gradle file
buildscript {
ext {
springBootVersion = '2.1.2.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
implementation 'org.springframework.boot:spring-boot-starter-web'
runtimeOnly 'org.postgresql:postgresql'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
This fixes my java problem, but I still cannot get it running as a spring boot application.
Please help as I am not sure where to continue!!! I need to be able to run this project as a spring boot application for backend services, as I will then be tasked with connecting it to frontend services with vue.js. (Don't worry i got that part)!
Here is my EventRegistration.java file as well
package ca.mcgill.ecse321.eventregistration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.SpringApplication;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;
#RestController
#SpringBootApplication
public class EventRegistrationApplication {
public static void main(String[] args) {
SpringApplication.run(EventRegistrationApplication.class, args);
}
#RequestMapping("/")
public String greeting() {
return "ECSE321 Event Registration Application - Backend base URL.\n"
+ "Use the API methods to interact with the backend!";
}
}

Though I stopped using eclipse but following used to solve situations like this
1.
- Eclipse ->preferences-->java-->installed JRE --> select a standard vm
(can find here jdk1.8.0_51.jdk/Contents/Home)
2.
- add the JRE System Library to your project build path
- right click project > select build path > libraries >
- if JRE is listed then good otherwise > add Library
- select JRE library and finish

Javalite framework - problem with locating existing FreeMarker templates

I am developing a simple web application which provides RestFul API for managing several resources.
I am using java standard edition - openjdk version "1.8.0_191 and the following javalite dependencies:
javalite-common-2.3-SNAPSHOT.jar
activejdbc-2.3-SNAPSHOT.jar
activeweb-2.3-SNAPSHOT.jar
activeweb-testing-2.3-SNAPSHOT.jar
freemarker-2.3.28.jar
I use embedded jetty v9.4.1 for web server and the whole project is packed as jar with dependencies and is run using the following command:
java -Dconfig=/etc/project/config.properties -jar jarname.jar
The web application is designed to serve only JSON and all FreeMarker templates construct json messages. Here is my FreeMarker config class:
public class FreeMarkerConfig extends AbstractFreeMarkerConfig {
#Override
public void init() {
// this is to override a strange FreeMarker default processing of numbers
Configuration config = this.getConfiguration();
config.setNumberFormat("0.##");
config.setClassicCompatible(true);
config.setClassForTemplateLoading(this.getClass(), "webapp/WEB-INF/views");
}
}
After the packaging the structure inside the jar is as follows (this is a simplified version with only one resource):
├── META-INF
│   ├── MANIFEST.MF
│   └── maven
│   └── project.control
│   └── panel
│   ├── pom.properties
│   └── pom.xml
├── activejdbc_models.properties
├── app
│   ├── config
│   │   ├── AppBootstrap.class
│   │   ├── AppControllerConfig.class
│   │   ├── DbConfig.class
│   │   ├── FreeMarkerConfig.class
│   │   └── RouteConfig.class
│   ├── controllers
│   │   ├── APIController.class
│   │   ├── CatchAllFilter.class
│   │   ├── OfficesController.class
│   └── models
│   ├── Office.class
├── config.properties
├── project
│   └── control
│   └── panel
│   ├── Launcher.class
│   ├── dao
│   │   ├── query
│   │   │   ├── Query.class
│   │   │   ├── QueryBuilder.class
│   │   │   ├── QueryStringBuilder.class
│   │   │   ├── StatsParamsHandler.class
│   │   └── validators
│   │   ├── OfficeValidator.class
│   ├── exceptions
│   │   └── ResourceNotFoundException.class
│   └── util
│   ├── Config.class
│   ├── JsonHelper.class
└── webapp
└── WEB-INF
├── views
│   ├── offices
│   │   ├── _comma.ftl
│   │   ├── _office.ftl
│   │   ├── _office_agency.ftl
│   │   ├── _office_agent.ftl
│   │   └── index.ftl
│   ├── layouts
│   │   └── default_layout.ftl
│   ├── shared
│   │   ├── _paging.ftl
│   │   └── message.ftl
│   ├── system
│   │   ├── 404.ftl
│   │   └── error.ftl
└── web.xml
Most of the time everything seems to operate normally and without any problems. But at some point something happens and FreeMarker is unable to locate the templates which were previously served multiple times.
I am not able to reproduce the behaviour on localhost so I am not able to debug it.
It happened several times while running on a server. The only observation I had is that it happens after several idle hours - i.e there were no requests for several hours, the next request fails because FreeMarker can't locate the needed template. Here is the exact exception which is thrown, when /offices is requested:
2019-06-24 15:22:50 - INFO LazyList:164 - {"sql":"SELECT * FROM offices ORDER BY id LIMIT 20 OFFSET 0 ","params":[],"duration_millis":2,"cache":"miss"}
2019-06-24 15:22:50 - INFO DB:164 - {"sql":"SELECT COUNT(*) FROM offices","params":[],"duration_millis":0}
2019-06-24 15:22:50 - INFO FreeMarkerTemplateManager:81 - Rendering template: '/offices/index.ftl' without layout.
2019-06-24 15:22:50 - INFO FreeMarkerTemplateManager:81 - Rendering template: '/shared/message.ftl' without layout.
2019-06-24 15:22:50 - INFO RequestDispatcher:360 - {"controller":"app.controllers.OfficesController","duration_millis":15,"remote_ip":"127.0.0.1","method":"GET","action":"index","error":"Failed to render template: '/shared/message.ftl' without layout. Template not found for name \\\"/shared/message.ftl\\\".\\nThe name was interpreted by this TemplateLoader: WebappTemplateLoader(subdirPath=\\\"/WEB-INF/views/\\\", servletContext={contextPath=\\\"\\\", displayName=\\\"activeweb\\\"}).","url":"http://127.0.0.1:5050/offices","status":404}
2019-06-24 15:22:50 - INFO FreeMarkerTemplateManager:81 - Rendering template: '/system/404.ftl' with layout: '/layouts/default_layout.ftl'.
2019-06-24 15:22:50 - ERROR RequestDispatcher:290 - ActiveWeb internal error:
org.javalite.activeweb.ViewMissingException: Failed to render template: '/system/404.ftl' with layout: '/layouts/default_layout.ftl'. Template not found for name "/system/404.ftl".
The name was interpreted by this TemplateLoader: WebappTemplateLoader(subdirPath="/WEB-INF/views/", servletContext={contextPath="", displayName="activeweb"}).
at org.javalite.activeweb.freemarker.FreeMarkerTemplateManager.merge(FreeMarkerTemplateManager.java:109)
at org.javalite.activeweb.RenderTemplateResponse.doProcess(RenderTemplateResponse.java:88)
at org.javalite.activeweb.ControllerResponse.process(ControllerResponse.java:67)
at org.javalite.activeweb.RequestDispatcher.renderSystemError(RequestDispatcher.java:283)
at org.javalite.activeweb.RequestDispatcher.doFilter(RequestDispatcher.java:219)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1613)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:541)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:190)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1584)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1228)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:168)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:481)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1553)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:166)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1130)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:564)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:112)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:672)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:590)
at java.lang.Thread.run(Thread.java:748)
Additional details can be provided in case of need.
What may cause such problems - while everything seems operational, suddenly FreeMaker can't locate templates which were previously served without any problems.
Any suggestions that may help for debugging the issue will be appreciated.
Thanks!

After more detailed investigation it appeared that jetty extracts the FreeMarker templates from the jar and places them in /tmp folder. The folder has the following pattern
/tmp/jetty-<host>-<port>-<resourceBase>-<context>-<virtualhost>-<randomdigits>.dir
Example:
jetty-0.0.0.0-5050-webapp-_-any-35239075401795634.dir
Unix based operation systems have policy for cleaning /tmp folder and after the folder is deleted - obviously the templates can't be found.
The solutions is to configure jetty's WebAppContext to use another directory for this kind of data. This can be done with setTempDirectory method:
String webViewsPath = Launcher.class.getResource("/webapp").toString();
WebAppContext webapp = new WebAppContext(webViewsPath, "/");
webapp.setTempDirectory(new File("/data/templates"));
server.setHandler(webapp);
More information for jetty's temporary directories can be found here:
https://www.eclipse.org/jetty/documentation/9.4.x/ref-temporary-directories.html

Multi-module Spring project: override a resource file in test

I have a Spring project with the following structure:
.
├── pom.xml
├── core-module
│   ├── pom.xml
│   └── src
│   ├── main
│   │   ├── java
│   │   └── resources
│   │   ├── applicationContext.xml
│   │   └── file.xml
│   └── test
│   ├── java
│   └── resources
│   ├── file.xml
│   └── foo.xml
└── web-module
├── pom.xml
└── src
├── main
│   └── java
└── test
└── java
In my applicationContext.xml file, I have the following import:
<import resource="classpath:file.xml" />
In production I want to use the file.xml defined in main, and during tests I want to use the one defined in the test folder; it's actually what is happenning when I run the tests of the core-module.
However, when I run the tests of the web-module, this is not the case, the file used is the one of the main folder.
How to perform what I want?
Some notes:
web-module has a test-jar dependency to core-module, so tests resources are included;
if I go inside the target directory, the file.xml is the good one in the test-classes folder;
when running web-module tests, if I put a breakpoint in the Spring code, then a getClass().getClassLoader().getResource() on file.xml returns the one defined in main, but if I run the same method on the foo.xml file it returns me the only one available in the test folder, so both files seems to be present, but it acts as if the main takes over the test resource...
Thank you!

SPI + JDK 9 + module-info.java

I am experimenting with SPI on JDK 9. Entire example works on JDK 9 without "module-info.java". After adding "module-info.java" ServiceLocator is not finding implementing class. I am confused and I cannot find working SPI example in modulerized JDK 9 project.
So my example project looks like this:
/spidemo
├── apiModule
│   ├── pom.xml
│   └── src
│   └── main
│   └── java
│   ├── eu
│   │   └── com
│   │   └── example
│   │   └── text
│   │   └── spi
│   │   └── TextAPI.java
│   └── module-info.java
├── applicationB
│   ├── pom.xml
│   └── src
│   └── main
│   ├── java
│   │   └── eu
│   │   └── com
│   │   └── example
│   │   └── spi
│   │   └── b
│   │   └── application
│   │   └── DemoB.java
│   └── module-info.java
├── applicationCommon
│   ├── pom.xml
│   └── src
│   └── main
│   └── java
│   ├── eu
│   │   └── com
│   │   └── example
│   │   └── spi
│   │   └── application
│   │   └── TextAPIProvider.java
│   └── module-info.java
├── implementationB
│   ├── pom.xml
│   └── src
│   └── main
│   ├── java
│   │   └── eu
│   │   └── com
│   │   └── example
│   │   └── implb
│   │   └── text
│   │   └── TextB.java
│   ├── module-info.java
│   └── resources
│   └── META-INF
│   └── services
│   └── eu.com.example.text.spi.TextAPI
I have introduced interface:
package eu.com.example.text.spi;
public interface TextAPI {
String getHelloWorldText();
}
This interface is implemented by:
package eu.com.example.implb.text;
import eu.com.example.text.spi.TextAPI;
public class TextB implements TextAPI {
public String getHelloWorldText() {
return "Text from B implementation";
}
}
The implementation is searched by code simmiliar to:
package eu.com.example.spi.application;
import eu.com.example.text.spi.DefaultTextAPI;
import eu.com.example.text.spi.TextAPI;
import java.util.ServiceLoader;
public class TextAPIProvider {
public static TextAPI getProvider(String providerName) {
ServiceLoader<TextAPI> serviceLoader = ServiceLoader.load(TextAPI.class);
for (TextAPI provider : serviceLoader) {
String className = provider.getClass().getName();
if (providerName.equals(className)) {
return provider;
}
}
throw new RuntimeException(providerName + " provider is not found!");
}
}
And now is the fun part. When I am executing class below without:
/implementationB/src/main/java/module-info.java
/applicationB/src/main/java/module-info.java
then implementation class is found and text is printed out.
package eu.com.example.spi.b.application;
import eu.com.example.spi.application.TextAPIProvider;
public class DemoB {
public static void main(String[] args) {
System.out.println("---> " + TextAPIProvider.getProvider("eu.com.example.implb.text.TextB").getHelloWorldText());
}
}
After introducing this two "module-info.java" files implementation class is not found by ServiceLocator.
Content of /applicationB/src/main/java/module-info.java:
module eu.com.example.applicationB {
requires eu.com.example.apiModule;
requires transitive eu.com.example.applicationCommon;
uses eu.com.example.text.spi.TextAPI;
}
Content of /implementationB/src/main/java/module-info.java:
module eu.com.example.implb.text {
requires eu.com.example.apiModule;
exports eu.com.example.implb.text;
// provides eu.com.example.implb.text.TextB with eu.com.example.text.spi.TextAPI;
}
When I uncomment:
provides eu.com.example.implb.text.TextB with eu.com.example.text.spi.TextAPI;
line then compilation error occurs:
.../implementationB/src/main/java/module-info.java:[7,74] the service implementation type must be a subtype of the service interface type, or have a public static no-args method named "provider" returning the service implementation
.../implementationB/src/main/java/module-info.java:[7,5] service implementation must be defined in the same module as the provides directive
I have tried to change package names as compilation error sugests, but then I have introduced "split package" issues.
What I should do to use ServiceLocator in fully modularized JDK 9? Is it possible? Have anyone seen working example?
Code can be also seen here: https://github.com/RadoslawOsinski/spidemo

You can change to using:-
provides eu.com.example.text.spi.TextAPI with eu.com.example.implb.text.TextB;
// you provide a service through its implementation
instead of
provides eu.com.example.implb.text.TextB with eu.com.example.text.spi.TextAPI;
Services in the document provides a sample around the implementation.

A module can specify that it provides a service with a specific type of service providers. It is declared using provides and with keyword.
syntax : provides serviceType with implementationTypes;
( Can specify multiple implementations types as a comma-separated list )
Therefore in your module eu.com.example.implb.text should add following statement.
provides eu.com.example.implb.text.TextB with eu.com.example.text.spi.TextAPI;
NOTE : provides does not equal exports. So any other modules that requires eu.com.example.implb.text will not access eu.com.example.implb.text.TextB if it doesn't exports.

How should my MANIFEST.MF look?

I have the following directly structure:
mp1
├── lib
│   └── kryonet-2.21-all.jar
├── mp1.iml
├── out
│   ├── artifacts
│   │   └── UX
│   │   ├── META-INF
│   │   │   └── MANIFEST.MF
│   │   └── UX.jar
├── src
│   ├── [.class files]
│   └── cs425
│   └── mp1
│   ├── agent
│   │   ├── [handlers].java
│   ├── common
│   │   ├── [commons].java
│   ├── main
│   │   └── UX.java
│   └── network
│   ├── [networks].java
I'm completely new to mainfest files, and am just trying to get a .jar to run on a remote box. My manifest looks like this right now:
Manifest-Version: 1.0
Main-Class: cs425.mp1.main.UX
But I just keep getting,
~/mp1$ java -jar UX.jar
Error: Invalid or corrupt jarfile UX.jar
Any help? I'm not sure what options to add for my external library and how to define my classpath.

It appears as though the only thing I was missing was the classpath to my external .jar file. My manifest now looks like:
Manifest-Version: 1.0
Main-Class: cs425.mp1.main.UX
Class-Path: kryonet-2.21-all.jar
After making sure all of my required files are part of the artifact package (my manifest file, external jar, etc), the issue seems to have gone away.