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Friday, April 22, 2022

Update to Spring > 2.5

 I've recently updated one of our spring boot apps. We've used Spring Boot 2.4 and I update to the latest available 2.6. After restarting the tests and test application I noticed a problem with the initialization of the h2 db. 

We tend to use the former spring datasource properties 


which are renamed into spring.sql.init.*. So I also renamed them, but nothing happened so far. Neither schema nor data.sql gets called during startup. After reading the changes I noticed a hint in the Init Docu that you should not use the init scripts with higher level db migration tools like liquibase and flyway.

We are using flyway and that was causing the issue. Form Spring Boot 2.5.1 on the init script will be ignored if you are using flyway or liquibase (spring boot doc).

So I changed the way we init the dev and test h2 db. I set the 


and removed the schema.sql and data.sql. To initially create and fill our db with flyway I added to flyway snippets using the flyway hook for beforeMigrate. As we have to script I used the standard flyway notation for the two scripts like the following



After that change fly way runs the two scripts before starting the migration when using the h2 db. I only added the two script to our flyway h2 snippets.


Wednesday, October 21, 2020

Self signed certificates and Oracle 19


Starting with Oracle 19 you need to do some additional steps to allow Java calls within your Oracle 19 db to access self signed web services or other ssl/https resources. You'll notice the problem with error like the following while calling an https site from java within Oracle 19:

ORA-29532: Java-Aufruf durch nicht abgefangene Java-Ausnahme beendet: java.rmi.RemoteException: java.rmi.RemoteException:; nested exception is: 

                HTTP transport error: javax.xml.soap.SOAPException: javax.xml.soap.SOAPException: Message send failed: PKIX path building failed: unable to find valid certification path to requested target

Copy the existing cacerts file located in /home/oracle/database/javavm/jdk/jdk8/lib/security/cacerts
to /home/oracle/database/javavm/jdk/jdk8/lib/security/cacerts.alt

add your self signed cert with (how to get my cert from an existing web site)

keytool -importcert -trustcacerts \
    -keystore /home/oracle/database/javavm/jdk/jdk8/lib/security/cacerts.alt \
    -storepass changeit \
    -file my_ca_cert.crt -alias myrootca \
    -v -noprompt

Load the file into oracle with sqlplus

$ sqlplus / as sysdba
SQL> alter session set container = orclpdb;
SQL> exec dbms_java.loadjava('-schema SYS -grant PUBLIC -dirprefix /home/oracle/database/javavm/jdk/jdk8 /home/oracle/database/javavm/jdk/jdk8/lib/security/cacerts.alt')

or with the CLI Tool 

$ cd /home/oracle/database/javavm/jdk/jdk8
$ loadjava -user sys@db -v -schema SYS -grant PUBLIC  \

Monday, July 13, 2020

Flyway spring.jpa.hibernate.ddl-auto=validate fails with Oracle synonyms

Using Flyway alongside with Hibernate is a nice matchmaker. Within one of the Spring Boot project I noticed that the flyway validate fails. Reason was a missing view. But looking deeper into the conf shows a synonym, which is handling the view. Doesn't appear within the dev env because the devs disabled the long running validate.

They got error messages like:

Schema-validation: missing table
Schema-validation: missing column

Easy to get rid of this within a spring boot app if you know how. Here is my thought on that:


will help Spring Boot to configure the hikari pool and the hibernate source to also use synonyms for the metadata exploration.
Take care to also add config for tomcat or any other pool, if you don't use the spring default hikari pool.

Tuesday, March 24, 2020

Windows Subsystem for Linux (WSL)

If you need a real linux shell on your Windows 10 system follow these steps

1. Ensure "Windows-Subsystem for Linux" is active on your machine with the following cmd in a admin power shell

Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux

2. Restart your machine if asked

3. Download the linux distribution of your choice via wget 
Invoke-WebRequest -Uri -OutFile Ubuntu.appx –UseBasicParsing
or within you browser
or even from the MS App Store. 

You'll find a list of distributions here 

4. Install distribution with
Add-AppxPackage .\Ubuntu.Appx
5. If you now search for Ubuntu in your start menu, you'll find your ready to rock linux console in windows

Friday, March 13, 2020

Appcelerator Titanium projects with IntelliJ

Developing Appcelerator mobile Apps is usually done within the Axway Appcelerator Studio. I'm using IntelliJ to develop most of my apps and here is the way how you could build and run you Appcelerator projects.

Open the project and create a package.json like this:

  "name": "my-app",
  "version": "1.0.0",
  "description": "Sample package.json for running titanium apps within IntelliJ.",
  "main": "index.js",
  "directories": {},
  "scripts": {
    "setup": "./node_modules/.bin/titanium sdk install 8.3.1.GA --default",
    "clean": "./node_modules/.bin/titanium clean",
    "build": "npm run build:android && npm run build:ios",
    "build:android": "./node_modules/.bin/titanium build -p android -b",
    "build:android:full": "npm run build:android",
    "build:ios": "./node_modules/.bin/titanium build -p ios -b",
    "build:ios:full": "npm run build:ios",
    "init:android": "npm install && npm run setup | $ANDROID_HOME/tools/bin/sdkmanager --licenses",
    "init:ios": "npm install",
    "android": "./node_modules/.bin/titanium build -p android -T emulator -C HUGO",
    "ios": "./node_modules/.bin/titanium build -p ios -T simulator -C HUGO",
    "download:android:sdk": "$ANDROID_HOME/tools/bin/sdkmanager \"platform-tools\" \"platforms;android-29\" \"build-tools;29.0.2\" \"emulator\" \"ndk-bundle\" \"system-images;android-29;google_apis_playstore;x86\"",
    "create:avd": "echo \"no\"| $ANDROID_HOME/tools/bin/avdmanager create avd -f -n Pixel_2_API_28 -k \"system-images;android-29;google_apis_playstore;x86\" -d \"pixel\"",
    "configure:avd": "for f in ~/.android/avd/*.avd/config.ini; do echo 'hw.keyboard=yes' >> \"$f\"; done",
    "prepare:env:android": "npm install && npm-run-all init:android download:android:sdk create:avd configure:avd"
  "author": "Andre Dvorak",
  "license": "GPL",
  "homepage": "",
  "devDependencies": {
    "npm-run-all": "4.1.5"
  "dependencies": {
    "alloy": "1.14.1",
    "titanium": "5.2.1"

To start a device session with your new app just open the package.json an select
  1. "setup" target
  2. "android" target 
After the build you will be asked you for the emulator of choice. You could skip this by replacing HUGO with the name of your favourite emulator.

OAuth2 and Open ID connect

OAuth2 is a standard protocol for authorisation. It is a framework which delegates the user authentication to a service, which manages the user accounts. It provides flows for web, desktop and mobile applications.

OpenID Connect is an extension of OAuth2. An OAuth2 server which implements OpenID connect is a so called OpenID provider (OP). The client of an OpenID connect server is called Relying Party (RP).
OpenID Connect offers the possibility to retrieve user profile information beside the access token defined within OAuth2. The user information is delivered within the payload of the id_token or within the access_token.
The following steps are the flow of the authorization code flow of an OP

  1. The RP open the app and clicks login
  2. The app starts an authorize request by opening the website which is defined within the authorization endpoint and specifies a redirect url
  3. The user fills in username and password or any information the OP needs to authorise it's user
  4. After the user click's continue on the login page the OP will redirect to the url specified in 2. and add an authorization code as a parameter to the redirect url
  5. The app fetches the authorization code and calls the token endpoint with the grant_type "authorization_code" to obtain an access token
  6. The OP will reply with an access token, refresh token and a lot of other field defined in oauth2 spec
  7. The app could now use the access token to authorize the logged in user
  8. Within the access token or as a separat id token the app could extract user profile information delivered by the OP

Tuesday, January 28, 2020

[ERROR] Unable to find suitable Xcode install

I was unable to build a titanium appcelerator based app on an iMac. My target was ios. So it seems to me that something must be missing within my xcode install.

Even if they are installed, configure your xcode cmd line tools. Go to


and check that the Command Line Tools are visible like in the following screen