How to create database tables from JPA using Hibernate
We know ORM. It will be a nightmare or a bliss based on the angle you are looking at it. This time a bliss
If you have started development from the java side and you have all the entities figured out, then hibernate can create the database for you from the entities.
For this example I will be assuming you are using Spring and Hibernate, with that, how do you create the database from the entities
Initial Setup assumptions
So, I will be assuming you have the spring being setup already, the configuration file for your application would look like:
jdbc.driverClassName = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql://localhost:3306/database
jdbc.username = root
jdbc.password = 123
hibernate.dialect = org.hibernate.dialect.MySQLDialect
hibernate.show_sql = true
hibernate.format_sql = true
hibernate.hbm2ddl.auto = create|create-drop|update|none
Here the values to
hibernate.hbm2ddl.auto could be create – if you want to crate during the sessionFactory initiation, create-drop, update when you want to update the exiting database when there is a change on the schema or none if you don’t want to do anything with it.
When working on spring framework, you might get this error specially on eclipse. I am assuming you are working on maven and eclipse environment.
ClassNotFound exception is a bit self explanatory that eclipse could not find the mentioned class
web.xml file for the spring configuration might look like
With this, you might have similar file like
application-context in the WEB-INF path
How to fix ClassNotFoundException for ContextLoaderList
The problem will during deployment. It is not basically compile time error. It is rather runtime error.
So, we have to make sure the jar responsible for this class is available in the classpath that eclipse is reading.
Pom dependency check
Make sure you have the same/similar configuration as the one listed below on your pom file.
You can have the right version for your spring in the parameter section or you can just replace it with the current version you have.
Using Deployment Assembly fix in eclipse
As we know, it is a deployment time problem, hence we have to tell the assembly where it can get its dependencies.
Right click on the project
Go to/search for Deployment Assembly
Click on Add
Select on Java Build path entries
Select all the maven dependencies
Clean and build the project
Either of the above methods should fix the problem
The superclass “javax.servlet.http.HttpServlet” was not found on the Java Build Path error in java webapp
If you are using eclipse, this might be due to project facet, right click on the project, go to project facet and select Runtimes and check the server you have configured.
if the app you are running is not spring or other web app framework that already comprised of servlet, then you need to add servlet to the build path.
You can add the servlet either through dependency management tools like gradle and maven or you can add it to the project lib file and compile it.
Also, you can add the dependency to servlet in your pom and get rid of the problem.
AbstractSureFireMojo Class error while running surefire test
mvn surefire:test or just
mvn test You might run into this issue.
It is missing the required dependency that you need to add in the pom file
Give it a try and let me know if it fix the problem
Spring data with spring boot error when using mapping
Spring boot has made life of the java developers a bliss. Thanks a million for the dedicated guys in spring.
Saying that, if you are working typical database related project with spring boot, you might have some error like this
java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:624) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:211) ~[tomcat-embed-core-8.5.16.jar!/:8.5.16]
Continue reading Spring Data error: getOutputStream() has already been called for this response
How to run single Test using Maven
If you want to run the whole test in maven then
will do the trick, but how about if you want to run single test
mvn -Dtest=SomeTest test
Where SomeTest is the name of the test you want to run
How to set JAVA_HOME ON MAC OSX computer
java_home as environment variable might be almost required especially when you use frameworks. Frameworks like
axis2 web server and others. Also some code editors require that too.
What is environment variable
Those are variables that would allow you to execute command line actions from any directory, basically from everywhere.
The simplest example is using
java -version. In this case, if you don’t have explicit environment variable on where to look for, it requires you to either be in the java folder or to fully list the whole path till bin folder.
Setting JAVA_HOME in mac osx
The first part is to make sure you have java installed in your machine.
If this is giving you an output with the version, then it means java is installed, otherwise, you should first install it.
The following task will be to find out where the binary files are located.
Click the apple icon on the left top corner of your mac and select system preferences..
And from there click Java and you will get the path information from there.
Once you got where the java is located, usually on
Open the bash properties file
And add the java path here
export JAVA_HOME=export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home
The above would be what it would look like fro jkd 1.8 on my El Capitan macbook pro.
hello world weblogic app server
There are lots of application servers for java and oracle weblogic is one of them. As of this writing the current and latest weblogic server is 12c
I will show a simple hello world tutorial on weblogic. The tutorial is for beginners of weblogic server.
This hello world weblogic tutorial assumes you have java skill already.
Installing weblogic server
First thing first, lets install and configure weblogic server
Continue reading hello world weblogic – hello world tutorial on weblogic
Simple servlet example – how to create servlet without eclipse
These days we are all surrounded by heavy frameworks that make life easier for us. Like maven, spring and hibernate and more. But how can we create a simple servlet website without the need of all those.
The main idea of servlet lies around very simple and intuitive files and structures. Knowing those only is good enough to built a good web app and that is what I will be showing here.
The main parts of the java web app are the following.
1. The Servlet – the java class that is handling the POST and GET http verbs
2. the deployment descriptor – web.xml. File telling how the webapp should be interacted like the url pattern
3. Servlet jar file – This is the jar handling the magic of interaction with the web for the servlet.
Structure of the webapp
Consuming SOAP tutorial from java step by step
SOAP, Simple Object Access Protocol, is older and still usable protocol for exchanging messages between systems.
Since soap is xml based, it is language and operating system independent. You can publish a soap service through your wsdl using Java on Linux and you can consume it through PHP application running on windows.
These days, SOAP is a bit lagging behind RESTful services which are rather more of architectural approaches than being protocol by themselves.
This is a tutorial showing how to consume an existing SOAP service using java language.
For this example, I will use a WSDL published on
In this one, I use already established wsdl for weather related tasks.
Eclipse has a nice tool to make life easier to consume SOAP related messages and I will show you here step by step.
Consuming SOAP tutorial step by step
1. Go ahead and create a new dynamic java project on your Eclipse
dynamic web project
Continue reading Consuming SOAP tutorial – Using java eclipse