Auto delete any metadata files that are unreadable (e.g. due to being empty, or invalid JSON).

src/main/java/org/qortal/arbitrary/metadata/ArbitraryDataMetadata.java

@@ -50,7 +50,7 @@ public class ArbitraryDataMetadata {
             this.readJson();
 
         } catch (JSONException e) {
-            throw new DataException(String.format("Unable to read JSON: %s", e.getMessage()));
+            throw new DataException(String.format("Unable to read JSON at path %s: %s", this.filePath, e.getMessage()));
         }
     }
 
@@ -64,6 +64,10 @@ public class ArbitraryDataMetadata {
         writer.close();
     }
 
+    public void delete() throws IOException {
+        Files.delete(this.filePath);
+    }
+
 
     protected void loadJson() throws IOException {
         File metadataFile = new File(this.filePath.toString());

src/main/java/org/qortal/controller/arbitrary/ArbitraryMetadataManager.java

@@ -102,7 +102,14 @@ public class ArbitraryMetadataManager {
                 if (metadataFile.exists()) {
                     // Use local copy
                     ArbitraryDataTransactionMetadata transactionMetadata = new ArbitraryDataTransactionMetadata(metadataFile.getFilePath());
-                    transactionMetadata.read();
+                    try {
+                        transactionMetadata.read();
+                    } catch (DataException e) {
+                        // Invalid file, so delete it
+                        LOGGER.info("Deleting invalid metadata file due to exception: {}", e.getMessage());
+                        transactionMetadata.delete();
+                        return null;
+                    }
                     return transactionMetadata;
                 }
             }