Hotfix Plain_GENERIC generating invalid java code

Hotfix weird generation of Plain method in LinkageProcessor
Add Plain for eager instantiation if using custom linkages not generating link or unlink method

src/de/steamwar/linkage/LinkageProcessor.java

@@ -279,7 +279,7 @@ public class LinkageProcessor extends AbstractProcessor {
                 linkages.computeIfAbsent(interfaceType.method(), s -> new ArrayList<>()).add(interfaceType);
             }
         }
-        if (!linkages.containsKey(plain_GENERIC.method())) {
+        if (linkages.size() == 1 && linkages.containsKey("unlink")) {
             linkages.put(plain_GENERIC.method(), Collections.singletonList(plain_GENERIC));
         }
         return linkages;

src/de/steamwar/linkage/api/Plain.java

@@ -0,0 +1,23 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2022  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.linkage.api;
+
+public interface Plain {
+}

src/de/steamwar/linkage/types/Plain_GENERIC.java

@@ -34,6 +34,6 @@ public class Plain_GENERIC implements LinkageType {
 
     @Override
     public void generateCode(BuildPlan buildPlan, MethodBuilder method, String instance, TypeElement typeElement) {
-        method.addLine(instance + ";");
+        if (instance.startsWith("new ")) method.addLine(instance + ";");
     }
 }