Fix 'occured' -> 'occurred' typos

src/java/org/apache/cassandra/exceptions/OperationExecutionException.java

@@ -23,7 +23,7 @@
 import org.apache.cassandra.db.marshal.AbstractType;
 
 /**
- * Thrown when an operation problem has occured (e.g. division by zero with integer).
+ * Thrown when an operation problem has occurred (e.g. division by zero with integer).
  */
 public final class OperationExecutionException extends FunctionExecutionException
 {

src/java/org/apache/cassandra/service/DiskErrorsHandlerService.java

@@ -54,12 +54,12 @@ public static synchronized void set(DiskErrorsHandler newInstance) throws Config
             }
             catch (Throwable t)
             {
-                logger.warn("Exception occured while closing disk error handler of class " + oldInstance.getClass().getName(), t);
+                logger.warn("Exception occurred while closing disk error handler of class " + oldInstance.getClass().getName(), t);
             }
         }
         catch (Throwable t)
         {
-            throw new ConfigurationException("Exception occured while initializing disk error handler of class " + newInstance.getClass().getName(), t);
+            throw new ConfigurationException("Exception occurred while initializing disk error handler of class " + newInstance.getClass().getName(), t);
         }
     }