Monday, December 14, 2009

Keytool keystore Cannot store non-PrivateKeys

Don't believe the error, or a lot of websites....

I have a requirement to encrypt passwords in a file. I figured I'd use the java security tools to store the encryption key.

Step 1/ Generate the secret key (Using AES as encryption algorithm)
.\keytool -genseckey -alias aestest -keyalg AES -keysize 192

This results in error
keytool error: Cannot store non-PrivateKeys

After much searching, and some incorrect pointers (Keytool cannot generate symmetric keys, keytool cannot generate AES keys etc.), I found the solution. The problem is the default Keystore type is JKS. This cannot store symmetric keys. However if you change the keystore type to JCEKS then it works.

.\keytool -genseckey -alias aestest -keyalg AES -keysize 192 -storetype JCEKS

One side effect of this is that you then need to specify the storeType in every command there-after.

keytool -list
keytool error: Invalid keystore format

keytool -list -storetype JCEKS
Your keystore contains 3 entries

aestest, 14-Dec-2009, SecretKeyEntry,
aestest2, 14-Dec-2009, SecretKeyEntry,
test, 14-Dec-2009, SecretKeyEntry,

Tuesday, November 10, 2009

Xquery to mask CreditCard number

declare function local:maskString($input as xs:string, $numClearDigits as xs:int)
as xs:string{
let $len := fn:string-length($input)
let $maskLen := $len - $numClearDigits
let $clearText := fn:substring($input, $maskLen+1)
let $mask := fn:string-join (
(for $i in (1 to $maskLen) return "X", $clearText)

Detect Java method name from code

public class MyTest {
public static void main(String args[]) {
new MyTest().doit();
public void doit() {
(new Exception().getStackTrace()[0].getMethodName());
The output

While the above snippet is not bad, it is expensive since we need to create an Exception.
With JDK1.5, a new technique is available.

public class Test {
public static void main(String args[]) {
new Test().doit();
public void doit() {
public void doitagain() {

public static void trace(StackTraceElement e[]) {
boolean doNext = false;
for (StackTraceElement s : e) {
if (doNext) {
doNext = s.getMethodName().equals("getStackTrace");


Tuesday, October 20, 2009

Mvn Mojo architype type

Quick note.

This maven page (on your first mojo) has a typo.

When creating a default mojo project using the architype the instruction says run

mvn archetype:create -DgroupId=quinn -DartifactId=maven-loop-task -DarchetypeGroupId=org.apache.maven.archetypes -DarchetypeArtifactId=maven-archetype-mojo

This fails. In fact you need to include the version attribute like so

mvn archetype:create -DgroupId=quinn -DartifactId=maven-loop-task -DarchetypeGroupId=org.apache.maven.archetypes -DarchetypeArtifactId=maven-archetype-mojo -DarchetypeVersion=1.0

Friday, September 04, 2009

USB drive won't go

I was been particularly stupid one day, trying to repartition my backup USB drive without first backing it up.

Yes I know I was stupid ,and frankly I probably deserved to lose everything, but I was lucky. The drive woulldn't appear on my laptop, and yet after running all the windows diagnostics , I could find no problems.

Running the following prog solved the problem


Select a drive letter and away you go.

Wednesday, July 08, 2009

Grails cheatsheet

Getting Started
grails set-proxy (if necessary to set proxy)
grails create-app AppName
cd AppName
grails create-domain-class Domain
grails generate-all Domain

Install Acegi
grails install-plugin acegi
grails create-auth-domains
grails generate-manager
grails generate-registration

grails schema-export (Export a DDL sql script for the domain classes)
grails generate-hbm-xml (Generate hibernate mapping file (From grails 1.3)
grails install-templates (Install base scaffolding files. Can then update them before generating scaffolding.
e.g. I update list default size to 50 (from 10)), Increase number of columns displayed in list tables (max by defauilt is 6 columns), changing if (i < 6){ { allows you to increase this (change in 2 places)

grails install-plugin db-stuff
grails create-db
grails export-data
grails export-data-diff
grails export-ddl
grails load-data

Maven integration
Build a new grails project with maven.
mvn org.apache.maven.plugins:maven-archetype-plugin:2.0-alpha-4:generate -DarchetypeGroupId=org.grails -DarchetypeArtifactId=grails-maven-archetype -DarchetypeVersion=1.2.0 -DgroupId=example -DartifactId=my-app

mvn initialize

  1. GORM Non numeric ID field
See my question, and someone elses helpful answer on the grails mailing list for how to create a non-numeric ID field, and rename it to something other than ID. Its a bit sneaky but works perfectly.
  1. Dependency Injection.
Ran into a stupid problem with Dependency injection. I was trying to inject the DataSource into a Service (and into a Java library). It appeared the Data source was not getting injected into grails Service class. Dependency injection was not working!!
As usual it was working fine, and the problem was mine...
Dependency Injection (DI) is configured by default to occur by name. If you create a property in your Domain/ Controller/ Service class with the same name as another Service or property you want injected, then it will automatically get injected. See this article
To inject the DataSource into your Service, All you need to do is add the line
def dataSource
to your Service. Thats all.. nothing else is needed.

I also had to add the following to initialize the java libraries dataSource, so I also needed
class BenefitService implements InitializingBean{
void afterPropertiesSet() {
println "Initializing BenefitService "+dataSource
This all would work. My problem was I (helpfully) added an accessor method for the dataSource
def getDataSource(){return dataSource)
This simple method modifies the groovy class dataSource property, effectively making the setter of the dataSource unavailable, thus effectively blocking dependency injection.
Moral: Groovy is designed to help reduce the number of code lines you write. Don't add unneccessary lines or there may be unexpected side-effects.

Monday, June 15, 2009

Shutdown hook in Groovy... Inner Classes in Groovy

Groovy doesn't support Inner classes directly. I was in a hurry to implement a shutdown hook in Java so I came accross the groovy workaround

I had to tweak the script slightly to get it to work for the shutdown hook (see below).

To implement the shutdown hook in Java a Thread instance is passed to the addShutdownHook() method of the Runtime instance.

In Java we could create an Inner class that extends Thread, or that implements Runnable.

In Groovy we must create a Map. The Map contains a list of key/ values. These correspond to method names (key), and method implementations (closure). For this case the closure will represent the Thread that we pass to the Runtime.addShutdownHook() method. Therefore we are implmenting the run() method, so the key in the map must be run().

The ProxyGenerator is then used to dynamically add the interface to the close. Finally since Runtime.addShutdownHook() expects a Thread instance (not simply a class that implements Runnable) ,we must add the Thread.class to the call to ProxyGenerator.instantiateAggregate().

def shutdownClosureMap = [run: {
println "Shutting down";
def interfaces = [Runnable]
def shutdownListener = ProxyGenerator.instantiateAggregate(shutdownClosureMap, interfaces, Thread.class)


Friday, June 12, 2009

Groovy GString/ STring

A few Gotchas that I've been getting stung with in Groovy.

GStrings and Strings

Be careful with Groovy Strings and Sql.

Make sure you know the rules of when Strings become GStrings, and therefore can support dynamic variable replacements.

GString docs can be found

These rules are listed here: (Note this doc is aproposal for changnig GString)

For example in the code below, if you simply use "def" to declare your variable, you will not see explicitly which types get converted to GStrings and which get converted to plain Strings.

By been explicit in your definitions however you can see that sql6 will not cast by default to a GString. This is becausei t is a multiline java.lang.String (see rules in link above). You will get this exception.

org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object "..." with class 'java.lang.String' to class 'groovy.lang.GString'

To fix it.

Date startDate = new Date() -1;
Date endDate = new Date();
def Format = "yyyy-MM-dd"
def OFormat = "YYYY-MM-DD"
String startString = startDate.format(Format);
String endString = endDate.format(Format);
println "Running between $startString and $endString";
def sql = []
def sql1 ="""
select * from prov_auditing_master m where EVENTTIMECOMPLETED > to_date($startString,$OFormat) and EVENTTIMECOMPLETED < sql2 =""> to_date($startString,$OFormat) and EVENTTIMECOMPLETED < sql3 =""> to_date($startString,$OFormat)"+
" and EVENTTIMECOMPLETED < sql4 =""> to_date($startString,$OFormat) and EVENTTIMECOMPLETED < sql5 =" "> to_date($startString,$OFormat) and EVENTTIMECOMPLETED < sql6 = ""> to_date($startString,$OFormat)"+
" and EVENTTIMECOMPLETED < db =" int" i="1">
println i+": $sq"

To fix

GString sql7 = "$sql6" ;
sql <<>

Tuesday, May 05, 2009

DB/ Database notes (sql tips)

JDBC Format 

Sybase  (jconn3.jar)

Use Service Name (format /)
user SID (format :)

Limit Rows

// mysql
select col from tbl limit 20;

//Sybase / SqlServer
select top 10 * from people
SET ROWCOUNT 10 // use SET ROWCOUNT 0 to turn off

// Oracle
select col from tbl where rownum <=20;

Using rank()

This query will return the top 10 rows..
select col1,col2 from (select rank() over (order by col1) r , col1,col2 from TABLE) where r<11 For bottom 10 rows use select col1,col2 from (select rank() over (order by col1 DESC) r , col1,col2 from TABLE) where r<11

Select unique

//Sybase / SqlServer
select distinct col from table



Outer Join

// Oracle left outer Join
select * from Customer, Order where Order.customerId (+) =
//right join
select * from Customer, Order where Order.customerId = (+)



>mysqldump --host --port=3306 -u datasift2 -p --set-gtid-purged=OFF datasift2  > datasift.sql
  • This will create a sql with all the tables. Note the --set-gtid-purged=OFF is required on newer versions of the client. If you are running on vc2c09mmk0326 it is probably not required.
  • Note the sql will be over 100MB in size

Oracle drop all tables
   FOR cur_rec IN (SELECT object_name, object_type
                     FROM user_objects
                    WHERE object_type IN
         IF cur_rec.object_type = 'TABLE'
            EXECUTE IMMEDIATE    'DROP '
                              || cur_rec.object_type
                              || ' "'
                              || cur_rec.object_name
                              || '" CASCADE CONSTRAINTS';
            EXECUTE IMMEDIATE    'DROP '
                              || cur_rec.object_type
                              || ' "'
                              || cur_rec.object_name
                              || '"';
         END IF;
         WHEN OTHERS
            DBMS_OUTPUT.put_line (   'FAILED: DROP '
                                  || cur_rec.object_type
                                  || ' "'
                                  || cur_rec.object_name
                                  || '"'

from Customer left join Order where Order.customerId =

Could only get this working by explicitly linking the join in the hbm file, and marking it as optional e.g.

Need some more testing to see if this can be done without updating the hbm file

<class name="AdjustmentCode" table="adjustment_code">
<id name="id" column="adjustment_code" type="string">
<generator class="native">
<property name="description" column="description" type="string">
<property name="adjustmentCode" column="adjustment_code" type="string" insert="false" update="false">
<join table="adjustment_message">optional="true">
<key column="adjustment_code">
Insert if row not Exists

// MySql
if not exists (select * from url where url = ...)
insert into url...

//Oracle (where not exists)
insert into <table> (<row1>, <row2>)
select <value1>, <value2> from dual
where not exists (
select * from <table> where <col1> = <value1>)

//SQL Server
if not exists (select * from url where url = ...)
insert into url...
Date Operations GetDate //MySql DATE() see ( //Oracle SYSDATE // Sql Server getDate() To Date //Oracle to_date('2009-01-01','YYYY-MM-DD') to_date('2009-05-19 18:32','YYYY-MM-DD HH24:MI') Detecting Duplicates (group by criteria) Say you want to detect duplicates (instances of more than one value) in a column. This is how to do it select dupCol, count(dupCol) from table group by dupCol having count(dupCol)>1 Listing Constrainsts Oracle SELECT * FROM USER_CONSTRAINTS WHERE TABLE_NAME = 'myTable';

Wednesday, April 15, 2009

Online XPath Tester

After looking for a quick online XPath Tester I decided to write my own.

This is an online xpath tool written in Javascript

Online XPath Tester

The following articles were helful in getting it running

Javascript Xpath tutorial

This article here is the Official Javascript guide to XPATH

These articles links to the Reference guides for XML. The  API for the XPath objects and the API for the w3c Xml objects

Not used here but useful nonetheless is a Javascript Reflection API. This article shows how to do it. I modified the code slightly to get it working

This article described

Friday, April 10, 2009

Weblogic Jms error.. "Peer Gone"

"It is likely that the remote side declared peer gone on this JVM"

This error had been causing me grief for a long time.

The problem was fixed by updating my etc hosts file on the client machine... (/windows/system32/drivers/etc/hosts on windows).

Some of our weblogic servers display the server name including domain name e.g. and some only display the server name (e.g. servername). By adding an entry for the target weblogic server in the etc/hosts the problem was fixed.

# For example:
# # source server
# # x client host localhost servername

Bea Articles on Oracle

When Oracle acquired BEa they began moving all the bea and weblogic sites into the domain.

Problem of course is that a lot of good articles are referenced on the web to their old original Bea urls.

This page lists where the equivilent sections exist on the oracle site

Overview of migration ->

Dev2dev and arch2arch ->

Weblogic JMS rollback

I was getting the following error in a Weblogic 9.2 deployment.

####<10-apr-2009> <info> <ejb> <vmmiddleware11> <mwalsb11> <[ACTIVE] ExecuteThread: '11' for queue: 'weblogic.kernel.Default (self-tuning)'> <<anonymous>> <> <> <1239355884374> <bea-010213> <message-driven xid="BEA1-23F28F44E9B311BE176F(110581804),Status="Rolled" reason="weblogic.transaction.internal.AppSetRollbackOnlyException],numRepliesOwedMe="0,numRepliesOwedOthers="0,seconds" begin="0,seconds" left="60,XAServerResourceInfo[WLStore_MWALSBDomain_JDBCStore_MWALSB11]="(ServerResourceInfo[WLStore_MWALSBDomain_JDBCStore_MWALSB11]="(state="rolledback,assigned="MWALSB11),xar="WLStore_MWALSBDomain_JDBCStore_MWALSB1146900074,re-Registered" state="rolledback),OwnerTransactionManager="ServerTM[ServerCoordinatorDescriptor="(CoordinatorURL="MWALSB11+vmmiddleware11:7011+MWALSBDomain+t3+," xaresources="{WLStore_MWALSBDomain_JDBCStore_MWALSB11," nonxaresources="{})],CoordinatorURL="MWALSB11+vmmiddleware11:7011+MWALSBDomain+t3+).">

First steps are to get more informative error messages by enabling debugging for JTA

This is done by adding the following switches to weblogic on startup


This article give a list of other possible switches available on Weblogic

Sunday, March 29, 2009

Google Map getting latitude and longitude


Search for wanted address. This will centre the location in the map.

Run the following command from the address bar



Thursday, January 08, 2009

ssh tunnels that stay alive

Don't have time for an explanation but heres a command to setup a ssh tunnel. (linux)

This will keep the tunnel alive after you logout, and also send keepAlive pings in order to stop any other proceses from deciding that its a dead link and shutting it down.

ssh -2 -x -L <localport>:<remotehost>:<remoteport> <remotelogin>@<remotehost> -N -n –f