Notes by Fang
Displaying keyword search results 1 - 10
Created by Fang on January 14, 2013 14:00:36
Last update: January 14, 2013 14:00:36
Cause: Hibernate reverse engineering generated a column mapping like this:
@Version
@Column(name="VERSION", nullable=false...
Fix: change the mapping to:
@Column(name="VERSION", length=20)
public Strin...
Created by Fang on May 15, 2012 13:04:24
Last update: May 15, 2012 13:04:44
Set the warnLogCategory attribute to log uncaught exception stacktrace:
<bean
class="org.springframework.web.servl...
Created by Fang on March 15, 2012 10:24:35
Last update: March 15, 2012 10:24:35
Suppose that I have an email field annotated with:
@NotEmpty(message="Please enter email address")
...
Bean validation will trigger two errors when no email address is entered:
the email field is empty
an empty email field is not a valid email address
Displaying both errors to the user with <form:errors> would be redundant and confusing:
<%@ taglib uri="http://www.springframework.org/tag...
This is how to display the first error only:
<spring:bind path="emailAddress">
<c:if test="$...
Created by Fang on February 27, 2012 12:19:19
Last update: February 27, 2012 12:19:19
Mapping Java objects to Jackson JSON is pretty simple. But if you name a JSON field wrong, you'll get the "Unrecognized field ... (Class ...), not marked as ignorable" error. The rule for mapping a Java bean attribute name to a JSON field name is: lower all leading capital letters until the first lower case letter .
For example, this Java class:
package com.example;
public class Person {
...
maps to this JSON string:
{
"firstName": "Jane",
"lastName": "...
Test code:
package com.example;
import java.net.URL;
...
Created by Fang on February 21, 2012 20:33:58
Last update: February 21, 2012 20:33:58
You can customize Tomcat error page with error code:
<error-page>
<error-code>404</error-code>
...
or Java exception type:
<error-page>
<exception-type>java.lang.Throwab...
Either error-code or exception-type is required, but not both. There's no way to aggregate error codes, such as:
<!-- This does not work! -->
<error-page>
...
Customizing error pages is about the only way to suppress the default stack trace in Tomcat in case of an unhandled exception.
Created by Fang on February 15, 2012 21:11:02
Last update: February 15, 2012 21:11:02
Error:
java.lang.NoClassDefFoundError: org/slf4j/helpers/...
Cause: had slf4j-nop as dependency, but did not have slf4j-api.
Solution: add dependency for slf4j-api.
<dependency>
<groupId>org.slf4j</groupId>
...
Created by Fang on February 15, 2012 21:03:57
Last update: February 15, 2012 21:03:57
Error:
java.lang.NoClassDefFoundError: org/slf4j/impl/Sta...
Soluton: add Maven dependency for one of slf4j-nop , slf4j-simple , slf4j-log4j12 , slf4j-jdk14 . For example:
<dependency>
<groupId>org.slf4j</groupId>
...
or
<dependency>
<groupId>org.slf4j</groupId>
...
org.hibernate.MappingException: An AnnotationConfiguration instance is required to use mapping class
Created by Fang on February 15, 2012 20:52:57
Last update: February 15, 2012 20:52:57
I got this error while using Hibernate 3.5.6:
org.hibernate.MappingException: An AnnotationConfi...
where I used annotations for mapping in the ExampleEntity class.
Problem : I initialized the session factory with Configuration :
sessionFactory = new Configuration()
.co...
Solution : should use AnnotationConfiguration instead:
sessionFactory = new AnnotationConfiguration()
...
Additional Note: Hibernate 4.1 didn't seem to mind ( Configuration worked fine).
Created by Fang on February 08, 2012 21:21:01
Last update: February 08, 2012 21:21:17
Just a reminder that I got this error when I set the Java system property javax.net.ssl.trustStore to a non-existing file (typo). The full error message when running Maven was:
[ERROR] java.lang.RuntimeException: Unexpected e...
Created by Fang on February 08, 2012 21:15:00
Last update: February 08, 2012 21:15:00
This was the error message:
[ERROR] sun.security.validator.ValidatorExceptio...
The certificate was actually signed by Verisign, but somehow failed to pass Java cert validation.
To resolve the problem:
Download the cert from the server (with RetrieveSSLCert , for example)
Import the certificate into the keystore:
$ keytool -import -trustcacerts -alias myserver -f...
Define MAVEN_OPTS :
$ export MAVEN_OPTS='-Djavax.net.ssl.trustStore=/h...
The quotes must exist for the value of MAVEN_OPTS , and the path must be absolute ( ~/etc/mavenKeyStore.jks does not work).
