JSP, MySQL and UTF-8 - mysql

I am going mental, international characters that I enter via a form are not being stored exactly as entered and the data stored is not being returned as its stored in the database.
If I enter 'çanak çömlek patladı' and click save on the form I use the page displays 'çanak çömlek patladı' but the database has stored 'çanak çömlek patlad? if I revisit the page again I get '￧anak ￧�mlek patlad?'' if I click save on the form without changing anything the database stores '?anak ??mlek patlad?' and the browser displays '?anak ??mlek patlad?'
I have my MySQL Server with the following config:
default-collation=utf8
collation_server=utf8_unicode_ci
character_set_server=utf8
default-character-set=utf8
The database character set is utf8 and database collation is utf8_unicode_ci and the table I am using is set as the same.
The first line of my JSP file is:
<%# page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
The html header is as so:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Test</title>
</head>
I have an EncodingFilter class compiled which is:
import java.io.IOException;
import javax.servlet.*;
public class EncodingFilter
implements Filter
{
public EncodingFilter()
{
}
public void init(FilterConfig filterconfig)
throws ServletException
{
filterConfig = filterconfig;
encoding = filterConfig.getInitParameter("encoding");
}
public void doFilter(ServletRequest servletrequest, ServletResponse servletresponse, FilterChain filterchain)
throws IOException, ServletException
{
servletrequest.setCharacterEncoding(encoding);
filterchain.doFilter(servletrequest, servletresponse);
}
public void destroy()
{
}
private String encoding;
private FilterConfig filterConfig;
}
This class is referenced in my web.xml file as follows:
<filter>
<filter-name>EncodingFilter</filter-name>
<filter-class>EncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>EncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
I’ve restarted my system and therefore the Tomcat and MySQL server, checked the logs and there are no errors with any of the above configuration.
Can anyone please help, otherwise I'll have no hair left?


Solved it, I ditched the previous db java class and wrote a new db function as it appeared that the previous developed class was causing a double encoding issue.
The error I was getting re the manual entering of 'çanak çömlek patladı' direct to the database related to an issue with MySQL not truly handing UTF-8 on varchar fields. As soon as I updated the field to varbinary, everything worked.
I hope this helps someone, I'm sure my hair will grow back, thank you to everyone who offered suggestions.


Before retrieving anything from database, execute SET NAMES UTF8 query and then all of the queries. You will then get the chars the way they look.


You need to check following things :
Your database should support multilingualism(If it's MySQL, at the time of installation itself it will ask your for this option).


Start with http://wiki.apache.org/tomcat/FAQ/CharacterEncoding#Q8
Your character-holding columns in MySQL will have to be able to accept UTF-8 characters. Most MySQL defaults are for latin1 character sets unless your DDL scripts set a character set for a column.
If you want to change a table from one encoding to another, you can do it like this:
mysql> ALTER TABLE t CONCERT TO CHARACTER SET 'utf8'
I think you can also do this on a column-by-column basis if you really want to as well. Note that ALTER may take a looooong time on tables with a lot of data, lots of indexes, etc.


When you connect to your database can you make sure you set "characterEncoding" as "utf8"?
Also, if you open your pages in a browser (eg. ffox) what is the character encoding that is being displayed?
I think you should try a bit of "divide et impera". It is important to learn if MYSQL is the problem or not (I suspect not). To do this you can insert the UTF String in your application and save it to the database. If this is not working we know the problem is mysql. If it works it is probably the servlet.
It wouldn't hurt to add this at the servlet level:
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");


I have got character encoding problems(JSP-Mysql).I wrote
String URL = "jdbc:mysql://localhost/deneme?useUnicode=true&characterEncoding=ISO-8859-1";
and solved the problem. But, database's table must UTF-8.

Related

how to take utf -8 characters from html form in spring controller characters like pi symbol , integration symbol

i have created virtual keyboard which contains special symbols like integration symbol , pi symbol but on submitting of form all virtual key board characters are showing like this âÏ? and spring controller in console also look like this âÏ? ,
in jsp header and all i changed to UTF-8 and project all page has a "UTF-8" and data base also has UTF-8. but symbols look correctly in input text ?
i tried in set content like UTF-8 and all
here is my spring controller method
//on submitting of page it is coming to here
#RequestMapping(value="/PostQueryAction",method=RequestMethod.POST)
public String question(#ModelAttribute UserQuestion userQuestion,HttpServletRequest httpServletRequest,ModelMap map,#RequestParam CommonsMultipartFile file,
HttpSession session) throws CustomException, Exception{
//here userquestion is my getters and setters
HttpSession ses = httpServletRequest.getSession();
httpServletRequest.setCharacterEncoding("UTF-8")

Issue while saving Non-English character

We are working with one application where we need to save data in language Gujarati.
Technologies used in Applcation is listed below.
Spring MVC Version 4.1.6.RELEASE
Hibernate Version 4.3.5.Final
MySQL 6.0.11
My JSP is configured with
<%# page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
And
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
Hibernate configuration is
<prop key="hibernate.connection.useUnicode">true</prop>
<prop key="hibernate.connection.characterEncoding">UTF-8</prop>
<prop key="hibernate.connection.charSet">UTF-8</prop>
MySQL URL is
jdbc:mysql://host:port/dbName?useUnicode=true&connectionCollation=utf8_general_ci&characterSetResults=utf8
Pojo having String field to store that data.
MySQL have VARCHAR datatype to store data with charset=utf8 and Collation=utf8_general_ci
When i tried to save any non-english(Gujrati) character it show some garbage character like àª?à«?àª? for "ગુજ".
Is there any other configuration which i missed here.

I was facing the same problem while inserting "tamil" characters into the database.After surfing a lot I got a better and working solution and it solves my problem.Here I am sharing my solution with you.I hope it will help you to clear your doubts regarding that Non English character.
INSERT INTO
STUDENT(name,address)
VALUES
(N'பெயர்', N'முகவரி');
I am using a sample since you have not provided me any structure of your table and field name.

I am assuming you want ગુજ (GA JA with Vowel sign U)?
I think you somehow specified "latin5". (Yes I see you have UTF-8 everywhere, but "latin5" is the only way I can make things work.)
CONVERT(CONVERT(UNHEX('C3A0C2AAC297C3A0C2ABC281C3A0C2AAC29C')
USING utf8) USING latin5) = 'ગુજ'
Plus you ended up with "double encoding"; I suspect this is what happened:
The client had characters encoded as utf8 (good); and
SET NAMES latin5 was used, but it lied by claiming that the client had latin5 encoding; and
The column in the table declared CHARACTER SET utf8 (good).
If possible, it would be better to start over -- empty the tables, be sure to have SET NAMES utf8 or establish utf8 when connecting from your client to the database. Then repopulate the tables.
If you would rather try to recover the existing data, this might work:
UPDATE ... SET col = CONVERT(BINARY(CONVERT(
CONVERT(UNHEX(col) USING utf8)
USING latin5)) USING utf8);
But you would need to do that for each messed up column in each table.
A partial test of that code is to do
SELECT CONVERT(BINARY(CONVERT(
CONVERT(UNHEX(col) USING utf8)
USING latin5)) USING utf8)
FROM table;
I say "partial test" because looking right may not prove that is right.
After the UPDATE, SELECT HEX(col) get E0AA97E0AB81E0AA9C for ગુજ. Note that most Gujarati hex should be of the form E0AAyy or E0AByy. You might also find 20 for a blank space.
I apologize for not being more certain. I have been tackling Character Set issues for a decade, but this is a new variant.

There might be a couple of things that you could have missed out. I had the same problem with mysql on linux, what I had to do is to edit my.cnf like this:
[client]
default-character-set = utf8
[mysqld]
character-set-server = utf8
For e.g. on Centos this file is location at /etc/my.cnf on Windows (my pc) C:\ProgramData\MySQL\MySQL Server 5.5\my.ini. Please note that ProgramData might be hidden.
Also the other thing if you are using Tomcat is that you have to sepcify UTF-8 for URI encoding. Just edit server.xml and modify your main Connector element:
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
URIEncoding="UTF-8"
redirectPort="8443" />
Also make sure you added character encoding filter in your application:
#WebFilter(filterName = "CharacterEncodingFilter", urlPatterns = {"/*"})
public class CharacterEncodingFilter implements Filter {
#Override
public void init(FilterConfig filterConfig)
throws ServletException {
}
#Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
request.setCharacterEncoding("UTF-8");
servletResponse.setContentType("text/html; charset=UTF-8");
filterChain.doFilter(request, servletResponse);
}
#Override
public void destroy() {
}
}
Hope this helps.

Another tip, don't lean only on setting the characterEncoding as a hibernate property <prop key="hibernate.connection.characterEncoding">UTF-8</prop>, make sure you add it explicitely as connection variable on the DB url, so
jdbc:mysql://host:port/dbName?useUnicode=true&characterEncoding=UTF-8&connectionCollation=utf8_general_ci&characterSetResults=utf8
Also, as there is some many layers where an encoding would be lost, you can try to isolate the layer and update to a question. E.g. if its upon storing to DB, or at some point before

Your applicationContext file should be like this:
To make Spring MVC application supports the internationalization, register two beans :
SessionLocaleResolver
Register a “SessionLocaleResolver” bean, named it exactly the same characters “localeResolver“. It resolves the locales by getting the predefined attribute from user’s session.
Note
If you do not register any “localeResolver”, the default AcceptHeaderLocaleResolver will be used, which resolves the locale by checking the accept-language header in the HTTP request.
LocaleChangeInterceptor
Register a “LocaleChangeInterceptor” interceptor and reference it to any handler mapping that need to supports the multiple languages. The “paramName” is the parameter value that’s used to set the locale.
<bean id="localeResolver"
class="org.springframework.web.servlet.i18n.SessionLocaleResolver">
<property name="defaultLocale" value="en" />
</bean>
<bean id="localeChangeInterceptor"
class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
<property name="paramName" value="language" />
</bean>
<bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping" >
<property name="interceptors">
<list>
<ref bean="localeChangeInterceptor" />
</list>
</property>
</bean>
<!-- Register the bean -->
<bean class="com.common.controller.WelcomeController" />
<!-- Register the welcome.properties -->
<bean id="messageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basename" value="welcome" />
</bean>
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
The native2ascii is a handy tool build-in in the JDK, which is used to convert a file with ‘non-Latin 1′ or ‘non-Unicode’ characters to ‘Unicode-encoded’ characters.
Native2ascii example
Create a file (source.txt)
Create a file named “source.txt”, put some Chinese characters inside, and save it as “UTF-8″ format.
native2ascii
Use native2ascii command to convert it into Unicode format.
C:>native2ascii -encoding utf8 c:\source.txt c:\output.txt
The native2ascii will read all the characters from “c:\source.txt” and encode it with “utf8″ format, and output all encoded characters to “c:\output.txt”
Read Output
Open the “c:\output.txt”, you will see the all encoded characters, e.g \ufeff\u6768\u6728\u91d1
welcome.properties
welcome.springmvc = \u5feb\u4e50\u5b66\u4e60
Call the above string and store the value in database.
And if you want to display that inside JSP page:
Remember add the line
“<%# page contentType=”text/html;charset=UTF-8″ %>”
on top of the jsp page, else the page may not able to display the UTF-8
(Chinese) characters properly.

org.hibernate.AssertionFailure: null id in entry (don't flush the Session after an exception occurs)

I have a hibernate and JSF2 application going to the deployment server and suddenly throwing an org.hibernate.AssertionFailure: null id in exception. I will provide the stack trace and code immediately but here are four important issues first:
This happens only on the deployment server (Jboss & MySql running on Windows Sever 2008.) It does not happen on my development machine (Tomcat and MySql running on Windoes 7 Pro) and also not on the staging environment (Jboss and MySql running on Linux.)
Researching this, it seems that people get this error when trying to insert an object. But I get the error when I'm doing a simple query. (various different queries, actually, as the error pops up on several pages randomly.)
The error hits only every now and then. If I do a Jboss restart it goes away, but a time later returns. Also, it's not consistent, on some clicks it's there, on others it's not. Even when it hits, when I do a simple refresh of the page it returns fine.
I'm using c3p0 (config below)
Any idea what's going on?
The code details:
This happens on an address object. Here's the full hbm:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.idex.auctions.model">
<class name="Address" table="address" lazy="true">
<id name="addressID" column="AddressID">
<generator class="native"/>
</id>
<property name="street" column="street"/>
<property name="city" column="city"/>
<property name="zip" column="zip"/>
<property name="state" column="state"/>
<property name="region" column="region"/>
<property name="country" column="country"/>
<many-to-one name="user"
class="com.idex.auctions.model.User"
column="userid"
unique="true"
cascade="save-update"/>
</class>
</hibernate-mapping>
The Java class is straight forward:
public class Address implements Serializable {
private static final long serialVersionUID = 7485582614444496906L;
private long addressID;
private String street;
private String city;
private String zip;
private String state;
private String region;
private String country;
private User user;
public Address() {
}
public long getAddressID() {
return addressID;
}
public void setAddressID(long addressID) {
this.addressID = addressID;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getRegion() {
return region;
}
public void setRegion(String region) {
this.region = region;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
The c3p0 configuration:
<property name="hibernate.c3p0.acquire_increment">1</property>
<property name="hibernate.c3p0.idle_test_period">1000</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.timeout">1800</property>
<property name="hibernate.c3p0.max_statements">0</property>
<property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
The versions used are
hibernate3.jar
c3p0-0.9.1.2.jar
myfaces-api-2.1.4.jar
myfaces-impl-2.1.4.jar
mysql-connector-java-5.1.20-bin.jar
The full stacktrace
org.hibernate.AssertionFailure: null id in com.idex.auctions.model.Address entry
(don't flush the Session after an exception occurs)
org.hibernate.event.def.DefaultFlushEntityEventListener.checkId(
DefaultFlushEntityEventListener.java:78)
org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(
DefaultFlushEntityEventListener.java:187)
org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(
DefaultFlushEntityEventListener.java:143)
org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(
AbstractFlushingEventListener.java:219)
org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(
AbstractFlushingEventListener.java:99)
org.hibernate.event.def.DefaultAutoFlushEventListener.onAutoFlush(
DefaultAutoFlushEventListener.java:58)
org.hibernate.impl.SessionImpl.autoFlushIfRequired(SessionImpl.java:997)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1142)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
com.idex.auctions.manager.DatabaseManager.getAllObjects(DatabaseManager.java:464)
com.idex.auctions.ui.NavBean.gotoHome(NavBean.java:40)
sun.reflect.GeneratedMethodAccessor350.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
javax.el.BeanELResolver.invokeMethod(BeanELResolver.java:735)
javax.el.BeanELResolver.invoke(BeanELResolver.java:467)
javax.el.CompositeELResolver.invoke(CompositeELResolver.java:246)
org.apache.el.parser.AstValue.getValue(AstValue.java:159)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
org.apache.myfaces.view.facelets.el.ContextAwareTagValueExpression.getValue(
ContextAwareTagValueExpression.java:96)
javax.faces.component._DeltaStateHelper.eval(_DeltaStateHelper.java:246)
javax.faces.component.UIOutcomeTarget.getOutcome(UIOutcomeTarget.java:50)
org.apache.myfaces.shared.renderkit.html.HtmlRendererUtils.getOutcomeTargetHref(
HtmlRendererUtils.java:1542)
org.apache.myfaces.shared.renderkit.html.HtmlLinkRendererBase.renderOutcomeLinkStart(
HtmlLinkRendererBase.java:908)
org.apache.myfaces.shared.renderkit.html.HtmlLinkRendererBase.encodeBegin(
HtmlLinkRendererBase.java:143)
javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:502)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:744)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:758)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:758)
org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.renderView(
FaceletViewDeclarationLanguage.java:1900)
org.apache.myfaces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:285)
com.ocpsoft.pretty.faces.application.PrettyViewHandler.renderView(
PrettyViewHandler.java:163)
javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:59)
org.apache.myfaces.tomahawk.application.ResourceViewHandlerWrapper.renderView(
ResourceViewHandlerWrapper.java:93)
com.idex.auctions.ui.CustomViewHandler.renderView(CustomViewHandler.java:98)
org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:115)
org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:241)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:199)
com.ocpsoft.pretty.PrettyFilter.doFilter(PrettyFilter.java:126)
com.ocpsoft.pretty.PrettyFilter.doFilter(PrettyFilter.java:118)

The exception:
org.hibernate.AssertionFailure: null id in entry (don't flush the Session after an exception occurs)
Tells us that the session exception has happened before the point where this org.hibernate.AssertionFailure is thrown.
To be exact, the org.hibernate.AssertionFailure is thrown when the session.flush() is happening, not the point where the error ocurred.
The above is a fact, thus a possible conclusion from it is: something could be suppressing the original exception.
So look for other possible points of error: A save() or saveOrUpdate() is possibly trying to persist an entity with a null field where, in the table, the column is NOT NULL?
TIP:
To help in the debugging, try adding a session.flush() after every interaction with the Session object (e.g. session.save(obj), session.merge(obj), etc.), this will hopefully cause the org.hibernate.AssertionFailure to happen earlier, closer to where the real problem is taking place. (Of course, after the debugging, remove those session.flush().)
In my case, the **real** exception was taking place inside a `try/catch {}` block where the `catch` suppressed the exception (didn't rethrow or warn me about it).

I would bet for a concurrency issue but it may occur at different levels:
a hibernate session may be shared between different users if the classical "open session in view" pattern is not properly implemented
an entity is shared between two user sessions because of improper hibernate cache settings
a JDBC connection is shared between two different hibernate session (less likely)
Apart from these potential sources of troubles, I would remove c3p0 (maybe just rumors...) as your stack already provides DataSource with connection pooling integrated with the transaction manager.

The #asdcjunior has answered correctly. Something has happened before the exception is thrown.
In that kind of situations (it happens often on integration tests when you dealing with single transaction for one test - for example #Transaction annotation) I'm invoking the method:
session.clear()
It helps because all the 'dirty' objects are removed from current session so when the next flush is executed the problem does not appear.
Example flow:
insert the assignment entity (many-to-many relation with constraint that could exist only single assignment) -> everything ok
insert the same assignment entity one more time -> everything ok, controller in this case return some kind of bad request exception, under the hood Spring throws the IntegrityViolationException -> in test everything looks ok
get the repository and execute findAll().size() to check the count of existed assigned to be sure that we have only single assignment -> the mentioned exception is thrown ;/ what happend? on the session exist still dirty object, normally the session would be destroyed (controller return error) but here we have the next assertions to check regarding database, so the solution here is additional session.clear() before next db related method executions
Example correct flow:
insert the assignment entity
insert the same assignment entity
session.clear()
get the repository and execute findAll().size()
Hope it helps ;)

You are probably hitting some Hibernate bug. (I'd recommend upgrading to at least Hibernate 3.3.2.GA.)
Meanwhile, Hibernate does better when your ID is nullable so that Hibernate can always tell the difference between a new object that has not yet been persisted to the database and one that's already in the database. Changing the type of addressID from long to Long will probably work around the problem.
The stack trace you provided shows that you are seeing the problem on a query because your query is forcing buffered writes to be flushed to the database before the query is executed and that write is failing, probably with the same insert problem other people are seeing.

I was facing this issue
I just add try catch block and in catch block I wrote seesion.clear();
now I can proceed with the rest of records to insert in database.

OK, I continued researching based among other things on other answers in this thread. But in the end, since we were up against a production deadline, I had to choose the emergency rout. So instead of figuring out hibernate I did these two things:
Removed a jQuery library I was using to grab focus on one of the forms. I did this because I read somewhere that this type of bug may happen due to a form posting a null value -- causing the null id down the line. I suspected the jQuery library may not sit well with PrimeFaces, and cause some form to malfunction. Just a hunch.
I killed the hibernate implemented relationship I had between user and address. (just one required, not one to many) and wrote the code myself when needed. Luckily it only affected one page significantly, so it wasn't much work.
The bottom line: we went live and the application has been running for several days without any errors. So this solution may not be pretty -- and I'm not proud of myself -- but I have a running app and a happy client.

Problem flow :
You create a new transient entity instance (here an Address instance)
You persist it to the database (using save, merge or persist in hibernate Session / JPA EntityManager)
As the entity identifier is generated by the database hibernate has to trigger the database insertion (it flushes the session) to retrieve the generated id
The insert operation trigger an exception (or any pending unflushed change in the session)
You catch the exception (without propagating it) and resume the execution flow (at this point your session still contains the unpersisted instance without the id, the problem is that hibernate seems to consider the instance as managed but the instance is corrupted as a managed object must have an id)
you reach the end of your unit of work and the session is automatically flushed before the current transaction is committed, the flush fails with an assertion failure as the session contains a corrupted instance
You have many possible ways to mitigate this error :
Simplest one and as hibernate stands "don't flush the Session after an exception occurs" ie. immediately give up and roll back the current transaction after a persistence exception.
Manually evict (JPA : detach) the corrupted instance from the session after catching the error (at point 5, but if the error was triggered by another pending change instead of the entity insert itself, this will be useless)
Don't let the database handle the id generation (use UUID or distributed id generation system, in this case the final flush will throw the real error preventing the persistence of the new instance instead of an hibernate assertion failure)

org.hibernate.AssertionFailure: null id in entry (don't flush the Session after an exception occurs)
This just happened to us and I thought I'd add some details for posterity. Turns out that we were trying to create an entity with a duplicate field that violated a condition:
Caused by: org.hibernate.exception.ConstraintViolationException: Duplicate entry '' for key
'Index_schools_name'
This exception however was being masked because hibernate was trying to commit the session even though the create failed. When the created failed then the id was not set hence the assert error. In the stack trace we could see that hibernate was committing:
at org.springframework.orm.hibernate4.HibernateTransactionManager.doCommit
(HibernateTransactionManager.java:480)
It should have been rolling back the session, not committing it. This turned out to be a problem with our rollback configuration. We are using the old XML configs and the exception path was incorrect:
<prop key="create*">PROPAGATION_REQUIRED,-org.x.y.LocalException</prop>
The LocalException path was incorrect and hibernate didn't throw an error (or it was buried in the startup log spew). This would probably also be the case if you are using the annotations and don't specify the right exception(s):
// NOTE: that the rollbackFor exception should match the throws (or be a subclass)
#Transactional(rollbackFor = LocalException.class)
public void create(Entity entity) throws AnotherException {
Once we fixed our hibernate wiring then we properly saw the "duplicate entry" exception and the session was properly being rolledback and closed.
One additional wrinkle to this was that when hibernate was throwing the AssertionFailure, it was holding a transaction lock in MySQL that then had to be killed by hand. See: https://stackoverflow.com/a/39397836/179850

This happened to me in the following situation:
New entity is persisted.
Entity is configured with javax.persistence.EntityListeners. javax.persistence.PostPersist runs.
PostPersist needs some data from the database to send a message via STOMP. A org.springframework.data.repository.PagingAndSortingRepository query is executed.
Exception.
I fixed it by using the following in the EntityListeners:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import java.time.Instant;
...
ThreadPoolTaskScheduler scheduler = ApplicationContextHolder.getContext().getBean(ThreadPoolTaskScheduler.class);
scheduler.schedule(() -> repository.query(), Instant.now());
Where ApplicationContextHolder is defined as:
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
#Component
public class ApplicationContextHolder implements ApplicationContextAware {
private static ApplicationContext context;
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
context = applicationContext;
}
public static ApplicationContext getContext() {
return context;
}
}

In my case the problem was the length parameter of an entity's field. When I tried to save an object with too long String value in one of its fields, I got the error. The solution was to set the proper value of parameter "length" in hibernate configuration.
<property name="status" type="string" length="150" not-null="false" access="field"/>
It can also be done with annotation #Length like that:
#Length(max=150)
private String status;
The hibernate exception's message was very misleading in my case, as was stacktrace. The fastest way to locate where the problem occures is to follow your code with debugger and evaluate session.flush(); after every save() and saveOrUpdate() method.

This is nothing to do with the Query that is being executed. This just triggers the flush. At this point Hibernate is trying to assign an identifier to the entity and seems to have failed for some reason.
Could you try changing the generator class:
<generator class="identity"/>
see if that makes a difference. Also have you made sure that the database you have deployed has the correct auto-incrementing column set up on the table?
It sounds like your issue is similar to this one.

Changing the generator class:
<generator class="identity" />
to
<generator class="assigned" />

I have the same exception too, in hibernate config file:
<property name="operateType" type="java.lang.Integer">
<column name="operate_type" not-null="true" />
</property>
when pass null value at object, occur exception
"org.hibernate.AssertionFailure: null id in com.idex.auctions.model.Address entry",
I think the reason because Hibernaye will check 'not-null' property, so, remove 'not-null' property or set 'not-null' for 'false', will resolve the problem.

Sometimes this happens when length of string is greater than that allowed by DB.
DataIntegrityViolationException translates to this exception which is a weird behavior by hibernate.
So if you have Column annotation on the String field of the entity with length specified and the actual value is greater than that length, above exception is thrown.
Ref: https://developer.jboss.org/thread/186341?_sscc=t

org.hibernate.AssertionFailure: null id in entry (don't flush the Session after an exception occurs)
Your getting this error while using the save method, if your maintaining the version history of the user activity and try to set the following values
setCreatedBy(1);
setModifiedBy(1);
setCreationDate();
setChangeDate();
}
You will get the above error to solve this you need to create the following columns on table.
Created_By
Modified_By
Creation_Date
Change_Date
if you are getting same error while Update method to solve this problem Just you need to change the Update() method to merge() method that it
i hope helped you.

I had the same error. In my case it was because before this exception I executing create query with exception. Exception is caught and don't rollback the transaction in catch block. Then I use this broken transaction in other operation and after a few time I got the same exception. At first I set flush mode to manual
public final Session getCurrentSession()
{
Session session = sessionFactory.getCurrentSession();
session.setFlushMode(FlushMode.MANUAL);
return session;
}
Then I got another exception, that explained to me what happened in fact. Then I done transaction rollback in catch block of my create method. And it helped to me.

I'm hitting the same error when I make session.getCurrentSession.refresh(entity) it looks more like a bug to me instead of an issue with my code. I'm getting this error in a unit test when I'm trying to refresh an entity in the beginning of a test and that entity is created in the test setup (annotated with junit's #Before). What is strange is that I'm creating 3 entities from the same class with random data at the same time and by the same way in the setup and I can refresh the first two created but the refresh fails for the last one. So for example If I create 3 entities User in the test setup I can refresh user1 and user2 and it fails for user3. I was able to resolve this by adding session.flush() at the end of the code that is creating the entity in the setup. I don't get any errors and I should but I cannot explain why the extra flush is needed. Also I can confirm that the entities are actually in the test DB even without flush because I can query them in the test but still failing the refresh(entity) method.

In my case, I traced out the error and found that I had not marked my table's primary key i.e. 'ID' as 'Auto_Increment' AI. Just tick the AI checkbox and it would work.

I don't know if im late or not, but my issue here was that i was opening an transaction and commiting -> flushing -> closing after the request. However between those did i have a nhibernate save() operator which does this automatically, in that case it complained.
Threw exception:
session.BeginTransaction();
model.save(entity);
session.Transaction.commit();
Solved for me
model.save(entity) //this one should open transaction, save and commit/flush by itself
However alot of people says that you should use both, ex NHibernate: Session.Save and Transaction.Commit.
But for some reason does it work for me now without transactions..

Roll back your transaction in the catch block

MVC3 - Can't enter long text into database

I'm making an extremely simple CMS in ASP.NET MVC 3 (just to learn it) but I've run into complications.
I'm using the EntityFramework (code first), and I'm trying to store articles in MySQL database (articles have standard properties like id, date, headline and content). My Create method is from some tutorial and looks as follows:
[HttpPost]
public ActionResult Create(Article newArticle)
{
if (ModelState.IsValid)
{
db.Articles.Add(newArticle);
db.SaveChanges();
return RedirectToAction("Index");
}
else
{
return View(newArticle);
}
}
I have generated a Create view (using razor engine) without changing anything. Everything works fine unless I try to enter longer text into the field for the "content" property (more than 20 or 30 words). Then I get a
System.Data.Entity.Validation.DbEntityValidationException
was unhandled by user code
error at the db.SaveChanges() line. I have tried changing the column I use for storing articles' content to text and then to nvarchar(max) (using Visual Studio's Server Explorer, I hade to change some setting before it let me do that) but it made no difference.
Is there anything obvious I'm missing?
I have pretty much no background in web and database development. Thanks in advance for any hints.

There is probably a mapping for the Content property that limits its size by default.
Try and decorate the Content property of your model with the StringLengthAttribute:
public class Article
{
[StringLength(4000)]
public string Content { get; set; }
}

Is this using EF4.1 RC?
I believe that this might be caused by the default length of varchars, which is set to 128.
ado.net blog post - as stated in the post, you might need to set the maxlength higher .
I believe that this is tested by EF itself, and not at the DB level and that's why your change did not help.

Uploading images with MYSQL blob type

Let's say I have this model:
#Entity
public class Picture extends Model {
public Blob image;
...
}
When I look the type in mysql database it is just the path to the attachments folder (VARCHAR). Is there some way to change this to save the binary data into mysql (BLOB) using play?
I would like to achieve this:
CREATE TABLE picture (
......
image blob,
...
);
Using JDBC to set the image:
"psmnt.setBinaryStream(3, (InputStream)fis, (int)(image.length()));"
I don't know if this makes sense at all but if not please explain me why! Why having attachments folder into play project?

Well, because storing media files (images/videos/audio/etc etc) is very uncommon (in the database), I'm guessing the team placed that Blob implementation to make it more "effective" instead of fetching binaries in the database (the database will be less hammered). To be honest I never used the Blob function, I know you can just implement your own Blob and have read a few posts about it.
http://groups.google.com/group/play-framework/browse_thread/thread/7e7e0b00a48eeed9
Do note like Guillaume said, Blob is the new version of the "File Attachment" class that was used early before 1.1. If you want to store an image and you are using hibernate
#Entity
public class Picture extends Model {
#Lob(type = LobType.BLOB)
public byte[] image;
...
}

In Play the Blob type stores only the hash reference to the file plus its mime type. The reason is that databases don't like too much big Blobs (for internal reason) and it's a good practice to store the files aside. It will also avoid you headaches related to encodings and backups, trust me (and more importantly, trust Play developers!)
As an alternative, you can store your image as:
#Entity
public class YourClass extends Model {
#Basic(fetch = FetchType.LAZY)
#Lob
public byte[] image;
public String mime_type;
public String file_name;
}
You will need to store the mime type separately (Blob type stores it in the database in the field) to be able to work with the file, and you might want to store the original file name given to you. To detect the mime type I would recommend to use mime-util.
As a last note, be aware that if you use Play's Blob, when you delete the field (via CRUD or the API) the file is not removed from the file system. You will need to create a Job that checks for unused files from time to time, to free space.
This happens (in Gillaume's words) due to the impossibility of having a safe 2-phase transaction between the database and the file system. this is relevant, as depending on your application you might find your file system filled up by unused images :)