Fix null pointer exception

README.md

@@ -5,11 +5,17 @@
 
 ### Difference from original skript-db
 - Fixed local variables disappearance in newer Skript versions (very hacky fix, but it works, so that's good!)
-- Thread-pool size is now automatically increasing on demand to use of CachedThreadPool, instead of a fixed hard-coded number
-- Uses a newer version of HikariCP
-- Only meant to be used by newer Minecraft versions (1.8 is not supported)
+- Thread-pool size is now automatically increasing on demand with use of CachedThreadPool, instead of a fixed hard-coded number
+- Uses newer versions of dependencies (Increased performance and security)
 - Replaced `synchronously execute` with `quickly execute`, which allows to speed up queries by 50ms with some risk
+- SQL Driver is configurable
+- A few variable type related bugs fixed
+- Uses Java 11 instead of Java 8
 
+### Installation
+1. Use Skript 2.5+
+2. Use Java 11+
+3. Put skript-db in plugins folder and restart the server
 ### Expression `Data Source` => `datasource`
 Stores the connection information for a data source. This should be saved to a variable in a
  `script load` event or manually through an effect command.
@@ -78,3 +84,10 @@ execute unsafe {fully dynamic query} in {sql}
 ```
 
 ---
+### Configuration
+plugins/skript-db/config.yml
+```
+# Only change this if you wish to use a different driver than Java's default, like MariaDB driver.
+# If you use MariaDB, its driver is shaded together with skript-db, so you can just specify: "org.mariadb.jdbc.Driver"
+sql-driver-class-name: "default"
+```

src/main/java/com/btk5h/skriptdb/skript/EffExecuteStatement.java

@@ -305,15 +305,17 @@ public class EffExecuteStatement extends Effect {
     private void setVariable(Event e, String name, Object obj) {
 
         //fix mediumblob and similar column types, so they return a String correctly
-        if (obj.getClass().getName().equals("[B")) {
-            obj = new String((byte[]) obj);
+        if (obj != null) {
+            if (obj.getClass().getName().equals("[B")) {
+                obj = new String((byte[]) obj);
 
-        //in some servers instead of being byte array, it appears as SerialBlob (depends on mc version, 1.12.2 is bvte array, 1.16.5 SerialBlob)
-        } else if (obj instanceof SerialBlob) {
-            try {
-                obj = new String(((SerialBlob) obj).getBinaryStream().readAllBytes());
-            } catch (IOException | SerialException ex) {
-                ex.printStackTrace();
+                //in some servers instead of being byte array, it appears as SerialBlob (depends on mc version, 1.12.2 is bvte array, 1.16.5 SerialBlob)
+            } else if (obj instanceof SerialBlob) {
+                try {
+                    obj = new String(((SerialBlob) obj).getBinaryStream().readAllBytes());
+                } catch (IOException | SerialException ex) {
+                    ex.printStackTrace();
+                }
             }
         }
         Variables.setVariable(name.toLowerCase(Locale.ENGLISH), obj, e, isLocal);