Minor cleanups of the JDBC code

java/jdbc/pom.xml

@@ -81,15 +81,6 @@
 
   <build>
     <plugins>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.5</version>
-        <configuration>
-          <source>7</source>
-          <target>7</target>
-        </configuration>
-      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>

java/jdbc/src/main/java/io/vitess/jdbc/VitessConnection.java

@@ -41,13 +41,11 @@
 import java.util.Properties;
 import java.util.Set;
 import java.util.concurrent.Executor;
-import java.util.logging.Logger;
 
 import io.vitess.client.Context;
 import io.vitess.client.VTGateConnection;
 import io.vitess.client.VTSession;
 import io.vitess.proto.Query;
-import io.vitess.proto.Vtgate;
 import io.vitess.util.CommonUtils;
 import io.vitess.util.Constants;
 import io.vitess.util.MysqlDefs;
@@ -58,7 +56,6 @@
 public class VitessConnection extends ConnectionProperties implements Connection {
 
     /* Get actual class name to be printed on */
-    private static Logger logger = Logger.getLogger(VitessConnection.class.getName());
     private static DatabaseMetaData databaseMetaData = null;
 
     /**
@@ -223,9 +220,8 @@ public void close() throws SQLException {
      * Return Connection state
      *
      * @return DatabaseMetadata Object
-     * @throws SQLException
      */
-    public boolean isClosed() throws SQLException {
+    public boolean isClosed() {
         return this.closed;
     }
 
@@ -486,19 +482,17 @@ public void setClientInfo(String name, String value) throws SQLClientInfoExcepti
      *
      * @param name - Property Name
      * @return Property Value
-     * @throws SQLException
      */
-    public String getClientInfo(String name) throws SQLException {
+    public String getClientInfo(String name) {
         return null;
     }
 
     /**
      * TODO: For Implementation Possibility
      *
      * @return - Property Object
-     * @throws SQLException
      */
-    public Properties getClientInfo() throws SQLException {
+    public Properties getClientInfo() {
         return null;
     }
 
@@ -818,11 +812,11 @@ private String initializeDBProperties() throws SQLException {
 
         if (metadataNullOrClosed()) {
             String versionValue;
-            ResultSet resultSet = null;
-            VitessStatement vitessStatement = new VitessStatement(this);
-            try {
-                resultSet = vitessStatement.executeQuery(
-                    "SHOW VARIABLES WHERE VARIABLE_NAME IN (\'tx_isolation\',\'INNODB_VERSION\', \'lower_case_table_names\')");
+
+            try(VitessStatement vitessStatement = new VitessStatement(this);
+                ResultSet resultSet = vitessStatement.executeQuery(
+                    "SHOW VARIABLES WHERE VARIABLE_NAME IN (\'tx_isolation\',\'INNODB_VERSION\', \'lower_case_table_names\')")
+            ) {
                 while (resultSet.next()) {
                     dbVariables.put(resultSet.getString(1), resultSet.getString(2));
                 }
@@ -855,13 +849,7 @@ private String initializeDBProperties() throws SQLException {
                 }
                 this.dbProperties =
                     new DBProperties(productVersion, majorVersion, minorVersion, isolationLevel, lowerCaseTables);
-            } finally {
-                if (null != resultSet) {
-                    resultSet.close();
-                }
-                vitessStatement.close();
             }
-
         }
         return dbEngine;
     }

java/jdbc/src/main/java/io/vitess/jdbc/VitessDriver.java

@@ -38,9 +38,6 @@
  */
 public class VitessDriver implements Driver {
 
-    /* Get actual class name to be printed on */
-    private static Logger logger = Logger.getLogger(VitessDriver.class.getName());
-
     static {
         try {
             DriverManager.registerDriver(new VitessDriver());
@@ -73,7 +70,7 @@ public Connection connect(String url, Properties info) throws SQLException {
      * TODO: Write a better regex
      */
     @Override
-    public boolean acceptsURL(String url) throws SQLException {
+    public boolean acceptsURL(String url) {
         return null != url && url.startsWith(Constants.URL_PREFIX);
     }
 

java/jdbc/src/main/java/io/vitess/jdbc/VitessPreparedStatement.java

@@ -48,7 +48,6 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
-import java.util.logging.Logger;
 
 import io.vitess.client.Context;
 import io.vitess.client.VTGateConnection;
@@ -70,7 +69,6 @@
 public class VitessPreparedStatement extends VitessStatement implements PreparedStatement {
 
     /* Get actual class name to be printed on */
-    private static Logger logger = Logger.getLogger(VitessPreparedStatement.class.getName());
     private final String sql;
     private final Map<String, Object> bindVariables;
     /**
@@ -394,7 +392,7 @@ public void addBatch() throws SQLException {
             vtGateConn = this.vitessConnection.getVtGateConn();
 
             this.retrieveGeneratedKeys = true; // mimicking mysql-connector-j
-            /**
+            /*
              * Current api does not support single query and multiple bindVariables list.
              * So, List of the query is created to match the bindVariables list.
              */
@@ -466,9 +464,6 @@ private int calculateParameterCount() throws SQLException {
                             continue; // inline quote escape
                         }
 
-                        inQuotes = !inQuotes;
-                        currentQuoteChar = 0;
-                    } else if (((c == '\'') || (c == '"')) && c == currentQuoteChar) {
                         inQuotes = !inQuotes;
                         currentQuoteChar = 0;
                     }

java/jdbc/src/main/java/io/vitess/jdbc/VitessResultSet.java

@@ -46,7 +46,6 @@
 import java.util.Calendar;
 import java.util.List;
 import java.util.Map;
-import java.util.logging.Logger;
 import javax.sql.rowset.serial.SerialClob;
 
 import io.vitess.client.cursor.Cursor;
@@ -61,9 +60,6 @@
  */
 public class VitessResultSet implements ResultSet {
 
-    /* Get actual class name to be printed on */
-    private static Logger logger = Logger.getLogger(VitessResultSet.class.getName());
-
     private Cursor cursor;
     private List<FieldWithMetadata> fields;
     private VitessStatement vitessStatement;
@@ -765,7 +761,7 @@ public Timestamp getTimestamp(String columnLabel, Calendar cal) throws SQLExcept
         return getTimestamp(columnIndex, cal);
     }
 
-    public boolean isClosed() throws SQLException {
+    public boolean isClosed() {
         return this.closed;
     }
 

java/jdbc/src/main/java/io/vitess/jdbc/VitessStatement.java

@@ -24,7 +24,6 @@
 import java.sql.Statement;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.logging.Logger;
 
 import io.vitess.client.Context;
 import io.vitess.client.Proto;
@@ -48,8 +47,6 @@
  */
 public class VitessStatement implements Statement {
     protected static final String[] ON_DUPLICATE_KEY_UPDATE_CLAUSE = new String[] { "ON", "DUPLICATE", "KEY", "UPDATE" };
-    /* Get actual class name to be printed on */
-    private static Logger logger = Logger.getLogger(VitessStatement.class.getName());
     protected VitessResultSet vitessResultSet;
     protected VitessConnection vitessConnection;
     protected boolean closed;
@@ -268,9 +265,8 @@ public SQLWarning getWarnings() throws SQLException {
     /**
      * Clear the warnings - Not saving Warnings
      *
-     * @throws SQLException
      */
-    public void clearWarnings() throws SQLException {
+    public void clearWarnings() {
         //no-op
     }
 
@@ -316,7 +312,7 @@ public VitessConnection getConnection() throws SQLException {
         return vitessConnection;
     }
 
-    public boolean isClosed() throws SQLException {
+    public boolean isClosed() {
         return this.closed;
     }
 
@@ -376,15 +372,15 @@ public ResultSet getGeneratedKeys() throws SQLException {
             }
         } else if (this.batchGeneratedKeys != null) {
             long totalAffected = 0;
-            for (int i = 0; i < this.batchGeneratedKeys.length; i++) {
-                long rowsAffected = this.batchGeneratedKeys[i][1];
+            for (long[] batchGeneratedKey : this.batchGeneratedKeys) {
+                long rowsAffected = batchGeneratedKey[1];
                 totalAffected += rowsAffected;
             }
             data = new String[(int) totalAffected][1];
             int idx = 0;
-            for (int i = 0; i < this.batchGeneratedKeys.length; i++) {
-                long insertId = this.batchGeneratedKeys[i][0];
-                long rowsAffected = this.batchGeneratedKeys[i][1];
+            for (long[] batchGeneratedKey : this.batchGeneratedKeys) {
+                long insertId = batchGeneratedKey[0];
+                long rowsAffected = batchGeneratedKey[1];
                 for (int j = 0; j < rowsAffected; j++) {
                     data[idx++][0] = String.valueOf(insertId + j);
                 }
@@ -591,7 +587,7 @@ protected void checkSQLNullOrEmpty(String sql) throws SQLException {
     protected int[] generateBatchUpdateResult(List<CursorWithError> cursorWithErrorList, List<String> batchedArgs)
         throws BatchUpdateException {
         int[] updateCounts = new int[cursorWithErrorList.size()];
-        ArrayList<long[]> generatedKeys = new ArrayList<long[]>();
+        ArrayList<long[]> generatedKeys = new ArrayList<>();
 
         Vtrpc.RPCError rpcError = null;
         String batchCommand = null;
@@ -663,7 +659,7 @@ protected void checkAndBeginTransaction() throws SQLException {
         if (!(this.vitessConnection.getAutoCommit() || this.vitessConnection.isInTransaction())) {
             Context context = this.vitessConnection.createContext(this.queryTimeoutInMillis);
             VTGateConnection vtGateConn = this.vitessConnection.getVtGateConn();
-            Cursor cursor = vtGateConn.execute(context,"begin",null,this.vitessConnection.getVtSession()).checkedGet();
+            vtGateConn.execute(context,"begin",null,this.vitessConnection.getVtSession()).checkedGet();
         }
     }