Revert "[WIP] Get JabRef running in eclipse" (#5280)

.gitmodules

@@ -1,3 +1,6 @@
+[submodule "src/main/resources/csl-styles"]
+	path = src/main/resources/csl-styles
+	url = https://github.com/citation-style-language/styles.git
 [submodule "src/main/resources/csl-locales"]
 	path = src/main/resources/csl-locales
 	url = https://github.com/citation-style-language/locales.git

eclipse.gradle

@@ -11,39 +11,17 @@ eclipseJdt.doLast {
     f.append('encoding/<project>=UTF-8')
 }
 eclipse {
-    project {
-        natures 'org.eclipse.buildship.core.gradleprojectnature'
-    }
-
-    classpath {
+//add libraries to module path: https://github.com/eclipse/buildship/issues/620#issuecomment-390469550
+ classpath {
         file {
             whenMerged {
-                entries.findAll { isModule(it) }.each { //(1)
-                    it.entryAttributes['module'] = 'true'
-                }
-
-                entries.findAll { isSource(it) && isTestScope(it) }.each {
-                    it.entryAttributes['test'] = 'true'
-                }
-
-                entries.findAll { isLibrary(it) && isTestScope(it) }.each {
-                    it.entryAttributes['test'] = 'true'
-                }
+                entries.findAll {
+                    it.kind == 'src' || it.kind == 'lib'
+                }.each { it.entryAttributes['module'] = 'true' }
             }
         }
-
-        defaultOutputDir = file('build')
-        downloadSources = true
-        downloadJavadoc = true
     }
 }
-
-boolean isLibrary(entry) { return entry.properties.kind.equals('lib') }
-boolean isTestScope(entry) { return entry.entryAttributes.get('gradle_used_by_scope').equals('test'); }
-boolean isModule(entry) { isLibrary(entry) && !isTestScope(entry); }
-boolean isSource(entry) { return entry.properties.kind.equals('src'); }
-
-
 // add formatter and cleanup settings to Eclipse settings
 // see http://stackoverflow.com/a/27461890/873282
 

src/main/java/org/jabref/JabRefMain.java

@@ -48,7 +48,7 @@ public static void main(String[] args) {
     public void start(Stage mainStage) throws Exception {
         try {
             // Fail on unsupported Java versions
-           // ensureCorrectJavaVersion();
+            ensureCorrectJavaVersion();
             FallbackExceptionHandler.installExceptionHandler();
 
             // Init preferences