diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..bb44f1ab7533335863d90be2c405eee133b92c8c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+out/
+build/
diff --git a/README.org b/README.org
index 8f79d7c38dd6d1112fb2e20e3326e884efb30b42..d0804e53369fbbd0de08de23ac0a23bad3505ef8 100644
--- a/README.org
+++ b/README.org
@@ -1,6 +1,6 @@
 * COMMENT -*- mode: org -*-
 #+Date: 2016-12-16
-Time-stamp: <2017-01-26>
+Time-stamp: <2019-02-23>
 
 * database binding benchmark
 I want to know the efficiency of the db binding for different language,
@@ -34,7 +34,7 @@ all build is release mode (with -O or equivalent).
 - Remarks:
   - python and go's db binding is as fast as C.
   - rust, haskell, cl is slower. C is 1.5x faster.
-  - racket is much slower. C is 5x faster.
+  - racket is much slower. C is 5x faster than racket.
 
 ** postgres 9.4, cpython 2.7, psycopg2==2.6.1
 http://initd.org/psycopg/docs/usage.html
@@ -163,3 +163,18 @@ https://www.postgresql.org/docs/9.4/static/libpq.html
   0.54
   28.51
   no effect.
+** 2019-02-23 on new ryzen5 PC. postgres 9.6 on M2 SSD. openjdk 1.8.0_162, jdbc postgresql 42.2.5
+warming up JVM...
+select time cost: 0.29s
+update time cost: 2.68s
+--
+warming up JVM...
+select time cost: 0.27s
+update time cost: 2.67s
+--
+select time cost: 0.35s
+update time cost: 2.72s
+--
+select time cost: 0.33s
+update time cost: 2.75s
+--
diff --git a/java-jdbc/Makefile b/java-jdbc/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..f65418146d06d9018867f8ce145f62997822de88
--- /dev/null
+++ b/java-jdbc/Makefile
@@ -0,0 +1,3 @@
+run:
+	PG_T1_PASSWORD="62IWgtWiPCZdt8qu" ./gradlew build run
+.PHONY: run
diff --git a/java-jdbc/build.gradle b/java-jdbc/build.gradle
new file mode 100644
index 0000000000000000000000000000000000000000..0dbad6d0a9300b8499ab3752a3ea2c76f34d17b9
--- /dev/null
+++ b/java-jdbc/build.gradle
@@ -0,0 +1,34 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java project to get you started.
+ * For more details take a look at the Java Quickstart chapter in the Gradle
+ * user guide available at https://docs.gradle.org/4.6/userguide/tutorial_java_projects.html
+ */
+
+plugins {
+    // Apply the java plugin to add support for Java
+    id 'java'
+
+    // Apply the application plugin to add support for building an application
+    id 'application'
+}
+
+// Define the main class for the application
+mainClassName = 'App'
+
+dependencies {
+    // This dependency is found on compile classpath of this component and consumers.
+    // compile 'com.google.guava:guava:23.0'
+    compile group: 'org.postgresql', name: 'postgresql', version: '42.2.5'
+
+    // Use JUnit test framework
+    testCompile 'junit:junit:4.12'
+}
+
+// In this section you declare where to find the dependencies of your project
+repositories {
+    // Use jcenter for resolving your dependencies.
+    // You can declare any Maven/Ivy/file repository here.
+    jcenter()
+}
diff --git a/java-jdbc/gradle/wrapper/gradle-wrapper.properties b/java-jdbc/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000000000000000000000000000000000000..bf3de218305ac2ca19cc7f8247373d3dd89edf84
--- /dev/null
+++ b/java-jdbc/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/java-jdbc/gradlew b/java-jdbc/gradlew
new file mode 100755
index 0000000000000000000000000000000000000000..cccdd3d517fc5249beaefa600691cf150f2fa3e6
--- /dev/null
+++ b/java-jdbc/gradlew
@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/java-jdbc/gradlew.bat b/java-jdbc/gradlew.bat
new file mode 100644
index 0000000000000000000000000000000000000000..e95643d6a2ca62258464e83c72f5156dc941c609
--- /dev/null
+++ b/java-jdbc/gradlew.bat
@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/java-jdbc/settings.gradle b/java-jdbc/settings.gradle
new file mode 100644
index 0000000000000000000000000000000000000000..dc2e96504cce83798868186a56432a7947edce3f
--- /dev/null
+++ b/java-jdbc/settings.gradle
@@ -0,0 +1,10 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * The settings file is used to specify which projects to include in your build.
+ * 
+ * Detailed information about configuring a multi-project build in Gradle can be found
+ * in the user guide at https://docs.gradle.org/4.6/userguide/multi_project_builds.html
+ */
+
+rootProject.name = 'db-binding-benchmark'
diff --git a/java-jdbc/src/main/java/App.java b/java-jdbc/src/main/java/App.java
new file mode 100644
index 0000000000000000000000000000000000000000..05e9e672bf1bda9d905e8eb3fc4d129843bd0c2c
--- /dev/null
+++ b/java-jdbc/src/main/java/App.java
@@ -0,0 +1,56 @@
+import java.sql.*;
+import java.util.Properties;
+
+/*
+ * This Java source file was generated by the Gradle 'init' task.
+ */
+public class App {
+    private static void runSelectTest(Connection conn, int times) throws SQLException {
+        Statement st = conn.createStatement();
+        ResultSet rs;
+        for (int i = 0; i < times; i++) {
+            rs = st.executeQuery("SELECT id, bar FROM foo");
+            while (rs.next()) {
+                rs.getInt(1);
+                rs.getInt(2);
+            }
+            rs.close();
+        }
+        st.close();
+    }
+
+    private static void runUpdateTest(Connection conn, int times) throws SQLException {
+        Statement st = conn.createStatement();
+        int r;
+        for (int i = 0; i < times; i++) {
+            r = st.executeUpdate("UPDATE foo SET bar=bar+1 WHERE id=1");
+            assert(r == 1);
+        }
+        st.close();
+    }
+
+    public static void main(String[] args) throws SQLException {
+        String url = "jdbc:postgresql://localhost/t1";
+        Properties props = new Properties();
+        props.setProperty("user", "t1");
+        String password = System.getenv("PG_T1_PASSWORD");
+        if (password == null || password.isEmpty()) {
+            System.out.println("Error: Please define PG_T1_PASSWORD environment variable");
+            System.exit(1);
+        }
+        props.setProperty("password", password);
+        props.setProperty("ssl", "false");
+        Connection conn = DriverManager.getConnection(url, props);
+
+        // warm up
+        System.out.println("warming up JVM...");
+        runSelectTest(conn, 3000);
+        long start = System.nanoTime();
+        runSelectTest(conn, 3000);
+        long selectFinish = System.nanoTime();
+        runUpdateTest(conn, 3000);
+        long updateFinish = System.nanoTime();
+        System.out.printf("select time cost: %.2fs\n", (selectFinish - start) / 1000000000.0);
+        System.out.printf("update time cost: %.2fs\n", (updateFinish - selectFinish) / 1000000000.0);
+    }
+}
diff --git a/java-jdbc/src/test/java/AppTest.java b/java-jdbc/src/test/java/AppTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..c5d3139a1c56b22f9add5dc4dda53b05eab3f2c4
--- /dev/null
+++ b/java-jdbc/src/test/java/AppTest.java
@@ -0,0 +1,11 @@
+/*
+ * This Java source file was generated by the Gradle 'init' task.
+ */
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class AppTest {
+    @Test public void testAppHasAGreeting() {
+        assertNull("app should have a greeting", null);
+    }
+}