Fix exception caused by loading the changelog too early

client/src/main/java/ctbrec/ui/tabs/UpdateTab.java

@@ -1,5 +1,10 @@
 package ctbrec.ui.tabs;
 
+import java.util.concurrent.CompletableFuture;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import ctbrec.io.HttpException;
 import ctbrec.ui.CamrecApplication;
 import ctbrec.ui.CamrecApplication.Release;
@@ -15,10 +20,8 @@ import javafx.scene.layout.Priority;
 import javafx.scene.layout.VBox;
 import okhttp3.Request;
 import okhttp3.Response;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-public class UpdateTab extends Tab {
+public class UpdateTab extends Tab implements TabSelectionListener {
 
     private static final Logger LOG = LoggerFactory.getLogger(UpdateTab.class);
 
@@ -37,14 +40,17 @@ public class UpdateTab extends Tab {
         vbox.setAlignment(Pos.CENTER);
         changelog = new TextArea();
         changelog.setEditable(false);
+        changelog.setText("Loading changelog...");
         vbox.getChildren().add(changelog);
         VBox.setVgrow(changelog, Priority.ALWAYS);
         setContent(vbox);
+    }
 
-        new Thread(() -> {
+    public void loadChangeLog() {
+        CompletableFuture.runAsync(() -> {
             Request req = new Request.Builder().url("https://pastebin.com/raw/fiAPtM0s").build();
-            try(Response resp = CamrecApplication.httpClient.execute(req)) {
-                if(resp.isSuccessful()) {
+            try (Response resp = CamrecApplication.httpClient.execute(req)) {
+                if (resp.isSuccessful()) {
                     changelog.setText(resp.body().string());
                 } else {
                     throw new HttpException(resp.code(), resp.message());
@@ -53,6 +59,16 @@ public class UpdateTab extends Tab {
                 LOG.error("Couldn't download the changelog", e1);
                 Dialogs.showError(getTabPane().getScene(), "Communication error", "Couldn't download the changelog", e1);
             }
-        }).start();
+        });
+    }
+
+    @Override
+    public void selected() {
+        loadChangeLog();
+    }
+
+    @Override
+    public void deselected() {
+        // nothing to do
     }
 }