Mitigates #3074 by avoiding NPE. Making the IDE work with system toolchains remains to be fixed

Author: Federico Fissore

arduino-core/src/processing/app/BaseNoGui.java

@@ -775,9 +775,11 @@ static private void createToolPreferences(ContributionsIndexer indexer) {
     PreferencesData.removeAllKeysWithPrefix(prefix);
 
     for (ContributedTool tool : indexer.getInstalledTools()) {
-      String path = tool.getDownloadableContribution().getInstalledFolder().getAbsolutePath();
-      PreferencesData.set(prefix + tool.getName() + ".path", path);
-      PreferencesData.set(prefix + tool.getName() + "-" + tool.getVersion() + ".path", path);
+      File installedFolder = tool.getDownloadableContribution().getInstalledFolder();
+      if (installedFolder != null) {
+        PreferencesData.set(prefix + tool.getName() + ".path", installedFolder.getAbsolutePath());
+        PreferencesData.set(prefix + tool.getName() + "-" + tool.getVersion() + ".path", installedFolder.getAbsolutePath());
+      }
     }
   }