JsonFileTypeFactory was removed in IntelliJ 2019.3.

[junghyun397]

After the 2019.03 update, I got the following error:

com.intellij.diagnostic.PluginException: While loading class eu.long1.flutter.i18n.arb.ArbFileTypeFactory: com/intellij/json/JsonFileTypeFactory [Plugin: FlutterI18n]
	at com.intellij.ide.plugins.cl.PluginClassLoader.loadClassInsideSelf(PluginClassLoader.java:223)
	at com.intellij.ide.plugins.cl.PluginClassLoader.tryLoadingClass(PluginClassLoader.java:167)
	at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:75)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	at java.base/java.lang.Class.forName0(Native Method)
	at java.base/java.lang.Class.forName(Class.java:398)
	at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getImplementationClass(ExtensionComponentAdapter.java:80)
	at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.createInstance(ExtensionComponentAdapter.java:39)
	at com.intellij.openapi.extensions.impl.XmlExtensionAdapter.createInstance(XmlExtensionAdapter.java:63)
	at com.intellij.openapi.extensions.impl.ExtensionPointImpl.processAdapter(ExtensionPointImpl.java:442)
	at com.intellij.openapi.extensions.impl.ExtensionPointImpl.processAdapter(ExtensionPointImpl.java:429)
	at com.intellij.openapi.extensions.impl.ExtensionPointImpl.processWithPluginDescriptor(ExtensionPointImpl.java:290)
	at com.intellij.openapi.extensions.ExtensionPointName.processWithPluginDescriptor(ExtensionPointName.java:157)
	at com.intellij.openapi.fileTypes.impl.FileTypeManagerImpl.initStandardFileTypes(FileTypeManagerImpl.java:358)
	at com.intellij.openapi.fileTypes.impl.FileTypeManagerImpl.<init>(FileTypeManagerImpl.java:228)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at com.intellij.serviceContainer.ConstructorInjectionKt.instantiateUsingPicoContainer(constructorInjection.kt:44)
	at com.intellij.serviceContainer.PlatformComponentManagerImpl.instantiateClassWithConstructorInjection(PlatformComponentManagerImpl.kt:505)
	at com.intellij.serviceContainer.ServiceComponentAdapter.createAndInitialize(ServiceComponentAdapter.kt:52)
	at com.intellij.serviceContainer.ServiceComponentAdapter.doCreateInstance(ServiceComponentAdapter.kt:39)
	at com.intellij.serviceContainer.BaseComponentAdapter.getInstanceUncached(BaseComponentAdapter.kt:110)
	at com.intellij.serviceContainer.BaseComponentAdapter.getInstance(BaseComponentAdapter.kt:72)
	at com.intellij.serviceContainer.BaseComponentAdapter.getInstance$default(BaseComponentAdapter.kt:65)
	at com.intellij.serviceContainer.PlatformComponentManagerImpl$preloadServices$future$1.run(PlatformComponentManagerImpl.kt:622)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
	at com.intellij.util.concurrency.BoundedTaskExecutor.doRun(BoundedTaskExecutor.java:222)
	at com.intellij.util.concurrency.BoundedTaskExecutor.access$200(BoundedTaskExecutor.java:30)
	at com.intellij.util.concurrency.BoundedTaskExecutor$1.execute(BoundedTaskExecutor.java:201)
	at com.intellij.util.concurrency.BoundedTaskExecutor$1.run(BoundedTaskExecutor.java:193)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NoClassDefFoundError: com/intellij/json/JsonFileTypeFactory
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:877)
	at com.intellij.util.lang.UrlClassLoader._defineClass(UrlClassLoader.java:359)
	at com.intellij.util.lang.UrlClassLoader.defineClass(UrlClassLoader.java:355)
	at com.intellij.util.lang.UrlClassLoader._findClass(UrlClassLoader.java:319)
	at com.intellij.ide.plugins.cl.PluginClassLoader.loadClassInsideSelf(PluginClassLoader.java:220)
	... 34 more
Caused by: java.lang.ClassNotFoundException: com.intellij.json.JsonFileTypeFactory PluginClassLoader[FlutterI18n, 0.0.6+1] com.intellij.ide.plugins.cl.PluginClassLoader@1e8c22ae
	at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:77)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	... 41 more

In the IJ 2019.03 API Changelog, I could find a replacement for com.intellij.json.JsonFileTypeFactory with com.intellij.fileType.
https://github.com/JetBrains/intellij-sdk-docs/blob/master/reference_guide/api_changes/api_changes_list_2019.md

..and I found a class in this project that extend JsonFileTypeFactory.
https://github.com/long1eu/flutter_i18n/blob/c8a26c6cdc28c12b94a280617d3838f09847c9bb/src/main/kotlin/eu/long1/flutter/i18n/arb/ArbFileTypeFactory.kt

[avimak]

pls see here - #125