diff --git a/src/main/java/org/embulk/output/BigqueryAuthentication.java b/src/main/java/org/embulk/output/BigqueryAuthentication.java
index a536dfa..84bfa97 100644
--- a/src/main/java/org/embulk/output/BigqueryAuthentication.java
+++ b/src/main/java/org/embulk/output/BigqueryAuthentication.java
@@ -47,9 +47,11 @@ public BigqueryAuthentication(String authMethod, Optional<String> serviceAccount
 
         if (authMethod.toLowerCase().equals("compute_engine")) {
             this.credentials = getComputeCredential();
-        } else if(authMethod.toLowerCase().equals("json_key")) {
+        }
+        else if (authMethod.toLowerCase().equals("json_key")) {
             this.credentials = getServiceAccountCredentialFromJsonFile();
-        } else {
+        }
+        else {
             this.credentials = getServiceAccountCredential();
         }
     }
@@ -111,4 +113,4 @@ public Bigquery getBigqueryClient() throws GoogleJsonResponseException, IOExcept
 
         return client;
     }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/org/embulk/output/BigqueryOutputPlugin.java b/src/main/java/org/embulk/output/BigqueryOutputPlugin.java
index d845b08..f8aff8c 100644
--- a/src/main/java/org/embulk/output/BigqueryOutputPlugin.java
+++ b/src/main/java/org/embulk/output/BigqueryOutputPlugin.java
@@ -146,7 +146,7 @@ public interface PluginTask
     }
 
     private final Logger log = Exec.getLogger(BigqueryOutputPlugin.class);
-    private final static String temporaryTableSuffix = Long.toString(System.currentTimeMillis());
+    private static final String temporaryTableSuffix = Long.toString(System.currentTimeMillis());
     private static BigqueryWriter bigQueryWriter;
 
     @Override
@@ -161,7 +161,8 @@ public ConfigDiff transaction(ConfigSource config, int taskCount,
             }
             try {
                 task.setP12Keyfile(Optional.of(LocalFile.of(task.getP12KeyfilePath().get())));
-            } catch (IOException ex) {
+            }
+            catch (IOException ex) {
                 throw Throwables.propagate(ex);
             }
         }
@@ -172,7 +173,8 @@ public ConfigDiff transaction(ConfigSource config, int taskCount,
             }
             try {
                 task.setSchemaFile(Optional.of(LocalFile.of(task.getSchemaPath().get())));
-            } catch (IOException ex) {
+            }
+            catch (IOException ex) {
                 throw Throwables.propagate(ex);
             }
         }
@@ -181,7 +183,8 @@ public ConfigDiff transaction(ConfigSource config, int taskCount,
             if (!task.getJsonKeyfile().isPresent()) {
                 throw new ConfigException("If auth_method is json_key, you have to set json_keyfile");
             }
-        } else if (task.getAuthMethod().getString().equals("private_key")) {
+        }
+        else if (task.getAuthMethod().getString().equals("private_key")) {
             if (!task.getP12Keyfile().isPresent() || !task.getServiceAccountEmail().isPresent()) {
                 throw new ConfigException("If auth_method is private_key, you have to set both service_account_email and p12_keyfile");
             }
@@ -200,7 +203,7 @@ public ConfigDiff transaction(ConfigSource config, int taskCount,
         }
 
         try {
-            bigQueryWriter = new BigqueryWriter.Builder (
+            bigQueryWriter = new BigqueryWriter.Builder(
                     task.getAuthMethod().getString(),
                     task.getServiceAccountEmail(),
                     task.getP12Keyfile().transform(localFileToPathString()),
@@ -222,7 +225,8 @@ public ConfigDiff transaction(ConfigSource config, int taskCount,
 
             bigQueryWriter.checkConfig(task.getProject(), task.getDataset(), task.getTable());
 
-        } catch (IOException | GeneralSecurityException ex) {
+        }
+        catch (IOException | GeneralSecurityException ex) {
             throw new ConfigException(ex);
         }
         // non-retryable (non-idempotent) output:
@@ -242,7 +246,8 @@ public ConfigDiff resume(TaskSource taskSource,
         if (mode == Mode.delete_in_advance) {
             try {
                 bigQueryWriter.deleteTable(project, dataset, generateTableName(tableName));
-            } catch (IOException ex) {
+            }
+            catch (IOException ex) {
                 log.warn(ex.getMessage());
             }
         }
@@ -255,13 +260,16 @@ public ConfigDiff resume(TaskSource taskSource,
                     bigQueryWriter.replaceTable(project, dataset, generateTableName(tableName) + "_old", generateTableName(tableName));
                 }
                 bigQueryWriter.replaceTable(project, dataset, generateTableName(tableName), generateTemporaryTableName(tableName));
-            } catch (TimeoutException | BigqueryWriter.JobFailedException | IOException ex) {
+            }
+            catch (TimeoutException | BigqueryWriter.JobFailedException | IOException ex) {
                 log.error(ex.getMessage());
                 throw Throwables.propagate(ex);
-            } finally {
+            }
+            finally {
                 try {
                     bigQueryWriter.deleteTable(project, dataset, generateTemporaryTableName(tableName));
-                } catch (IOException ex) {
+                }
+                catch (IOException ex) {
                     log.warn(ex.getMessage());
                 }
             }
@@ -328,7 +336,8 @@ public void nextFile()
                     }
                     log.info(String.format("Writing file [%s]", filePath));
                     output = new BufferedOutputStream(new FileOutputStream(filePath));
-                } catch (FileNotFoundException ex) {
+                }
+                catch (FileNotFoundException ex) {
                     throw Throwables.propagate(ex);
                 }
                 fileIndex++;
@@ -339,7 +348,8 @@ private void closeFile()
                 if (output != null) {
                     try {
                         output.close();
-                    } catch (IOException ex) {
+                    }
+                    catch (IOException ex) {
                         throw Throwables.propagate(ex);
                     }
                 }
@@ -349,9 +359,11 @@ public void add(Buffer buffer)
             {
                 try {
                     output.write(buffer.array(), buffer.offset(), buffer.limit());
-                } catch (IOException ex) {
+                }
+                catch (IOException ex) {
                     throw Throwables.propagate(ex);
-                } finally {
+                }
+                finally {
                     buffer.release();
                 }
             }
@@ -367,7 +379,8 @@ public void finish()
                             log.info(String.format("Delete local file [%s]", filePath));
                             file.delete();
                         }
-                    } catch (NoSuchAlgorithmException | TimeoutException | BigqueryWriter.JobFailedException | IOException ex) {
+                    }
+                    catch (NoSuchAlgorithmException | TimeoutException | BigqueryWriter.JobFailedException | IOException ex) {
                         log.error(ex.getMessage());
                         throw Throwables.propagate(ex);
                     }
@@ -447,15 +460,24 @@ public enum Mode
         append("append"),
         delete_in_advance("delete_in_advance") {
             @Override
-            public boolean isDeleteInAdvance() { return true; }
+            public boolean isDeleteInAdvance()
+            {
+                return true;
+            }
         },
         replace("replace") {
             @Override
-            public boolean isReplaceMode() { return true; }
+            public boolean isReplaceMode()
+            {
+                return true;
+            }
         },
         replace_backup("replace_backup") {
             @Override
-            public boolean isReplaceMode() { return true; }
+            public boolean isReplaceMode()
+            {
+                return true;
+            }
         };
 
         private final String string;
@@ -465,8 +487,17 @@ public enum Mode
             this.string = string;
         }
 
-        public String getString() { return string; }
-        public boolean isReplaceMode() { return false; }
-        public boolean isDeleteInAdvance() { return true; }
+        public String getString()
+        {
+            return string;
+        }
+        public boolean isReplaceMode()
+        {
+            return false;
+        }
+        public boolean isDeleteInAdvance()
+        {
+            return true;
+        }
     }
 }
diff --git a/src/main/java/org/embulk/output/BigqueryWriter.java b/src/main/java/org/embulk/output/BigqueryWriter.java
index 69219a6..6dbb930 100644
--- a/src/main/java/org/embulk/output/BigqueryWriter.java
+++ b/src/main/java/org/embulk/output/BigqueryWriter.java
@@ -72,7 +72,8 @@ public BigqueryWriter(Builder builder)
 
         if (autoCreateTable) {
             this.tableSchema = createTableSchema();
-        } else {
+        }
+        else {
             this.tableSchema = null;
         }
     }
@@ -100,7 +101,8 @@ private String getJobStatus(String project, JobReference jobRef) throws JobFaile
                 log.info(String.format("Job statistics [%s]", statistics.getLoad()));
             }
             return jobStatus;
-        } catch (IOException ex) {
+        }
+        catch (IOException ex) {
             log.warn(ex.getMessage());
             return "UNKNOWN";
         }
@@ -118,14 +120,17 @@ private void getJobStatusUntilDone(String project, JobReference jobRef) throws T
                 if (jobStatus.equals("DONE")) {
                     log.info(String.format("Job completed successfully. job id:[%s] elapsed_time:%dms status:[%s]", jobRef.getJobId(), elapsedTime, "SUCCESS"));
                     break;
-                } else if (elapsedTime > jobStatusMaxPollingTime * 1000) {
+                }
+                else if (elapsedTime > jobStatusMaxPollingTime * 1000) {
                     throw new TimeoutException(String.format("Checking job status...Timeout. job id:[%s] elapsed_time:%dms status:[%s]", jobRef.getJobId(), elapsedTime, "TIMEOUT"));
-                } else {
+                }
+                else {
                     log.info(String.format("Checking job status... job id:[%s] elapsed_time:%dms status:[%s]", jobRef.getJobId(), elapsedTime, jobStatus));
                 }
                 Thread.sleep(jobStatusPollingInterval * 1000);
             }
-        } catch (InterruptedException ex) {
+        }
+        catch (InterruptedException ex) {
             log.warn(ex.getMessage());
         }
     }
@@ -171,13 +176,15 @@ public void executeLoad(String project, String dataset, String table, String loc
 
         try {
             jobRef = insert.execute().getJobReference();
-        } catch (IllegalStateException ex) {
+        }
+        catch (IllegalStateException ex) {
             throw new JobFailedException(ex.getMessage());
         }
         log.info(String.format("Job executed. job id:[%s] file:[%s]", jobRef.getJobId(), localFilePath));
         if (isSkipJobResultCheck) {
             log.info(String.format("Skip job status check. job id:[%s]", jobRef.getJobId()));
-        } else {
+        }
+        else {
             getJobStatusUntilDone(project, jobRef);
         }
     }
@@ -203,19 +210,22 @@ public void copyTable(String project, String dataset, String fromTable, String t
 
         try {
             jobRef = insert.execute().getJobReference();
-        } catch (IllegalStateException ex) {
+        }
+        catch (IllegalStateException ex) {
             throw new JobFailedException(ex.getMessage());
         }
         log.info(String.format("Job executed. job id:[%s]", jobRef.getJobId()));
         getJobStatusUntilDone(project, jobRef);
     }
 
-    public void deleteTable(String project, String dataset, String table) throws IOException {
+    public void deleteTable(String project, String dataset, String table) throws IOException
+    {
         try {
             Tables.Delete delete = bigQueryClient.tables().delete(project, dataset, table);
             delete.execute();
             log.info(String.format("Table deleted. project:%s dataset:%s table:%s", delete.getProjectId(), delete.getDatasetId(), delete.getTableId()));
-        } catch (GoogleJsonResponseException ex) {
+        }
+        catch (GoogleJsonResponseException ex) {
             log.warn(ex.getMessage());
         }
     }
@@ -238,7 +248,8 @@ private JobConfigurationLoad setLoadConfig(String project, String dataset, Strin
             config.setSchema(tableSchema);
             config.setCreateDisposition("CREATE_IF_NEEDED");
             log.info(String.format("table:[%s] will be create if not exists", table));
-        } else {
+        }
+        else {
             config.setCreateDisposition("CREATE_NEVER");
         }
         return config;
@@ -252,7 +263,8 @@ private JobConfigurationTableCopy setCopyConfig(String project, String dataset,
 
         if (append) {
             config.setWriteDisposition("WRITE_APPEND");
-        } else {
+        }
+        else {
             config.setWriteDisposition("WRITE_TRUNCATE");
         }
 
@@ -294,7 +306,8 @@ public TableSchema createTableSchema() throws IOException
             ObjectMapper mapper = new ObjectMapper();
             List<TableFieldSchema> fields = mapper.readValue(stream, new TypeReference<List<TableFieldSchema>>() {});
             return new TableSchema().setFields(fields);
-        } finally {
+        }
+        finally {
             if (stream != null) {
                 stream.close();
             }
@@ -306,7 +319,8 @@ public boolean isExistTable(String project, String dataset, String table) throws
         Tables tableRequest = bigQueryClient.tables();
         try {
             Table tableData = tableRequest.get(project, dataset, table).execute();
-        } catch (GoogleJsonResponseException ex) {
+        }
+        catch (GoogleJsonResponseException ex) {
             return false;
         }
         return true;
@@ -317,13 +331,15 @@ public void checkConfig(String project, String dataset, String table) throws IOE
         if (autoCreateTable) {
             if (!schemaPath.isPresent()) {
                 throw new FileNotFoundException("schema_file is empty");
-            } else {
+            }
+            else {
                 File file = new File(schemaPath.orNull());
                 if (!file.exists()) {
                     throw new FileNotFoundException("Can not load schema file.");
                 }
             }
-        } else {
+        }
+        else {
             if (!isExistTable(project, dataset, table)) {
                 throw new IOException(String.format("table [%s] is not exists", table));
             }
@@ -347,7 +363,8 @@ private String getLocalMd5hash(String filePath) throws NoSuchAlgorithmException,
 
             byte[] encoded = (hashedBytes);
             return new String(encoded);
-        } finally {
+        }
+        finally {
             stream.close();
         }
     }
@@ -490,7 +507,8 @@ public BigqueryWriter build() throws IOException, GeneralSecurityException
 
     public class JobFailedException extends RuntimeException
     {
-        public JobFailedException(String message) {
+        public JobFailedException(String message)
+        {
             super(message);
         }
     }