DBZ-9708 Fix task getErrorHandler throws NullPointerException

Author: seanshi007

debezium-connector-mariadb/src/main/java/io/debezium/connector/mariadb/MariaDbConnectorTask.java

@@ -321,7 +321,7 @@ protected List<SourceRecord> doPoll() throws InterruptedException {
 
     @Override
     protected Optional<ErrorHandler> getErrorHandler() {
-        return Optional.of(errorHandler);
+        return Optional.ofNullable(errorHandler);
     }
 
     private MariaDbValueConverters getValueConverters(MariaDbConnectorConfig connectorConfig) {

debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/MongoDbConnectorTask.java

@@ -263,7 +263,7 @@ public List<SourceRecord> doPoll() throws InterruptedException {
 
     @Override
     protected Optional<ErrorHandler> getErrorHandler() {
-        return Optional.of(errorHandler);
+        return Optional.ofNullable(errorHandler);
     }
 
     @Override

debezium-connector-mysql/src/main/java/io/debezium/connector/mysql/MySqlConnectorTask.java

@@ -291,7 +291,7 @@ public List<SourceRecord> doPoll() throws InterruptedException {
 
     @Override
     protected Optional<ErrorHandler> getErrorHandler() {
-        return Optional.of(errorHandler);
+        return Optional.ofNullable(errorHandler);
     }
 
     @Override

debezium-connector-oracle/src/main/java/io/debezium/connector/oracle/OracleConnectorTask.java

@@ -240,7 +240,7 @@ public List<SourceRecord> doPoll() throws InterruptedException {
 
     @Override
     protected Optional<ErrorHandler> getErrorHandler() {
-        return Optional.of(errorHandler);
+        return Optional.ofNullable(errorHandler);
     }
 
     @Override

debezium-connector-postgres/src/main/java/io/debezium/connector/postgresql/PostgresConnectorTask.java

@@ -391,7 +391,7 @@ public List<SourceRecord> doPoll() throws InterruptedException {
 
     @Override
     protected Optional<ErrorHandler> getErrorHandler() {
-        return Optional.of(errorHandler);
+        return Optional.ofNullable(errorHandler);
     }
 
     @Override

debezium-connector-sqlserver/src/main/java/io/debezium/connector/sqlserver/SqlServerConnectorTask.java

@@ -206,7 +206,7 @@ public List<SourceRecord> doPoll() throws InterruptedException {
 
     @Override
     protected Optional<ErrorHandler> getErrorHandler() {
-        return Optional.of(errorHandler);
+        return Optional.ofNullable(errorHandler);
     }
 
     @Override