Add a servlet which can cause DB connection leaks.

src/main/java/org/t246osslab/easybuggy/troubles/DBConnectionLeakServlet.java

@@ -0,0 +1,87 @@
+package org.t246osslab.easybuggy.troubles;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Locale;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.pmw.tinylog.Logger;
+import org.t246osslab.easybuggy.utils.ApplicationUtils;
+import org.t246osslab.easybuggy.utils.Closer;
+import org.t246osslab.easybuggy.utils.MessageUtils;
+
+@SuppressWarnings("serial")
+@WebServlet(urlPatterns = { "/dbconnectionleak" })
+public class DBConnectionLeakServlet extends HttpServlet {
+
+    static final String dbUrl = ApplicationUtils.getDatabaseURL();
+    static final String dbDriver = ApplicationUtils.getDatabaseDriver();
+    boolean isLoad = false;
+
+    protected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
+
+        PrintWriter writer = null;
+        Connection conn = null;
+        Statement stmt = null;
+        Locale locale = req.getLocale();
+        try {
+            res.setCharacterEncoding("UTF-8");
+            res.setContentType("text/plain");
+            writer = res.getWriter();
+
+            if (dbDriver != null && !dbDriver.equals("")) {
+                try {
+                    Class.forName("com.mysql.jdbc.Driver");
+                } catch (ClassNotFoundException e) {
+                    Logger.error(e);
+                }
+            }
+            conn = DriverManager.getConnection(dbUrl);
+            stmt = conn.createStatement();
+            if (!isLoad) {
+                isLoad = true;
+                try {
+                    stmt.executeUpdate("drop table users3");
+                } catch (SQLException e) {
+                    // ignore exception if exist the table
+                }
+                // create and insert users table
+                stmt.executeUpdate("create table users3 (id int primary key, name varchar(30), password varchar(100))");
+            }
+            stmt.executeUpdate("insert into users3 select count(*)+1, 'name', 'password' from users3");
+            writer.println(MessageUtils.getMsg("msg.db.connection.leak.occur", locale));
+
+        } catch (SQLException e) {
+            Logger.error(e);
+            writer.println(MessageUtils.getMsg("msg.unknown.exception.occur", locale));
+            writer.println(e.getLocalizedMessage());
+        } finally {
+            Closer.close(writer);
+            /* A DB connection leaks because the following lines are commented out.
+            if (stmt != null) {
+                try {
+                    stmt.close();
+                } catch (SQLException e) {
+                    Logger.error(e);
+                }
+            }
+            if (conn != null) {
+                try {
+                    conn.close();
+                } catch (SQLException e) {
+                    Logger.error(e);
+                }
+            }
+             */
+        }
+    }
+}