add testcase & remove unused code

src/main/java/com/alibaba/druid/filter/FilterAdapter.java

@@ -2429,11 +2429,6 @@ public abstract class FilterAdapter extends NotificationBroadcasterSupport imple
         chain.statement_clearBatch(statement);
     }
 
-    @Override
-    public void statement_clearWarnings(FilterChain chain, StatementProxy statement) throws SQLException {
-        chain.statement_clearWarnings(statement);
-    }
-
     @Override
     public void statement_close(FilterChain chain, StatementProxy statement) throws SQLException {
         chain.statement_close(statement);
@@ -2543,6 +2538,11 @@ public abstract class FilterAdapter extends NotificationBroadcasterSupport imple
         return chain.statement_getQueryTimeout(statement);
     }
 
+    @Override
+    public void statement_setQueryTimeout(FilterChain chain, StatementProxy statement, int seconds) throws SQLException {
+        chain.statement_setQueryTimeout(statement, seconds);
+    }
+
     @Override
     public ResultSetProxy statement_getResultSet(FilterChain chain, StatementProxy statement) throws SQLException {
         return chain.statement_getResultSet(statement);
@@ -2573,6 +2573,11 @@ public abstract class FilterAdapter extends NotificationBroadcasterSupport imple
         return chain.statement_getWarnings(statement);
     }
 
+    @Override
+    public void statement_clearWarnings(FilterChain chain, StatementProxy statement) throws SQLException {
+        chain.statement_clearWarnings(statement);
+    }
+
     @Override
     public boolean statement_isClosed(FilterChain chain, StatementProxy statement) throws SQLException {
         return chain.statement_isClosed(statement);
@@ -2621,11 +2626,6 @@ public abstract class FilterAdapter extends NotificationBroadcasterSupport imple
         chain.statement_setPoolable(statement, poolable);
     }
 
-    @Override
-    public void statement_setQueryTimeout(FilterChain chain, StatementProxy statement, int seconds) throws SQLException {
-        chain.statement_setQueryTimeout(statement, seconds);
-    }
-
     @Override
     public <T> T unwrap(FilterChain chain, Wrapper wrapper, Class<T> iface) throws SQLException {
         return chain.unwrap(wrapper, iface);

src/main/java/com/alibaba/druid/pool/DruidPooledStatement.java

@@ -18,6 +18,7 @@ package com.alibaba.druid.pool;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.sql.SQLFeatureNotSupportedException;
 import java.sql.SQLWarning;
 import java.sql.Statement;
 import java.util.ArrayList;
@@ -65,10 +66,6 @@ public class DruidPooledStatement extends PoolableWrapper implements Statement {
         return conn;
     }
 
-    public void setPoolableConnection(DruidPooledConnection conn) {
-        this.conn = conn;
-    }
-
     public Statement getStatement() {
         return stmt;
     }
@@ -603,11 +600,11 @@ public class DruidPooledStatement extends PoolableWrapper implements Statement {
     }
 
     public void closeOnCompletion() throws SQLException {
-
+        throw new SQLFeatureNotSupportedException();
     }
 
     public boolean isCloseOnCompletion() throws SQLException {
-        return false;
+        throw new SQLFeatureNotSupportedException();
     }
 
     @SuppressWarnings("unchecked")

src/main/java/com/alibaba/druid/pool/StatementCacheAlgorithm.java

@@ -1,20 +0,0 @@
-/*
- * Copyright 1999-2011 Alibaba Group Holding Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.alibaba.druid.pool;
-
-public enum StatementCacheAlgorithm {
-    LRU, Fixed
-}