Problems reading Log4j.xml from outside web application

Problems reading Log4j.xml from outside web application

If you try to read the log4j.xml from outside the Spring application/classpath, you might get the following errors, if you are deploying a war file:

Stack trace

org.springframework.web.util.Log4jConfigListener failed: java.lang.IllegalStateException: Cannot set web app root system property when WAR file is not expanded.

java.lang.IllegalStateException: Cannot set web app root system property when WAR file is not expanded

                        at org.springframework.web.util.WebUtils.setWebAppRootSystemProperty(WebUtils.java:137)

                        at org.springframework.web.util.Log4jWebConfigurer.initLogging(Log4jWebConfigurer.java:117)

                        at org.springframework.web.util.Log4jConfigListener.contextInitialized(Log4jConfigListener.java:45)

The explanation is given below:

http://static.springsource.org/spring/docs/2.0.x/api/org/springframework/web/util/Log4jConfigListener.html

Summary -  org.springframework.web.util.Log4jConfigListener only works if the WAR file is exploded

The same with HDIV

Configuration

log4jConfigLocation
file:/${CONFIG_LOCATION}/log4j.xml
 

Solution

To override this we need to add the following to the web.xml

<context-param></context-param>
    <param-name>log4jExposeWebAppRoot</param-name>
<param-value>false</param-value>

Generated keys not requested. You need to specify Statement.RETURN_GENERATED_KEYS to Statement.executeUpdate() using Spring JdbcTemplate

My colleague was getting this exception for a Spring JdbcTemplate based code which I had written for some simple Mysql dao functionalities. The funny point was that we were both using the same version of Mysql drivers, but I was using 32bit Mysql 5.5 but my colleague was using the 64bit version.

This quick fix solves the problem:

KeyHolder keyHolder = new GeneratedKeyHolder();
jdbcTemplate.update(new PreparedStatementCreator() {
@Override
 public PreparedStatement createPreparedStatement(Connection aConnection) throws SQLException {
                    PreparedStatement preparedStatement = aConnection.prepareStatement(SAVE_USER, PreparedStatement.RETURN_GENERATED_KEYS);
                    preparedStatement.setString(....);
                    ....

                         preparedStatement.setString(....);

                    return preparedStatement;
                }
            }, keyHolder);
 user.setId(keyHolder.getKey().intValue());

A few other fellow bloggers had given suggestions like switching the Mysql dirvers, but it's didn't help me at all. I had tried all the last 10 Mysql driver releases. I am not sure if its a programming error or a Mysql bug, but the above code does fix the problem!

Happy Hacking :)

org.springframework.beans.FatalBeanException: Could not copy properties from source to target

I came across this irritating issue(While workign on a Spring based project).

org.springframework.beans.FatalBeanException: Could not copy properties from source to target; nested exception is java.lang.IllegalArgumentException: argument type mismatch

at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:599)

at org.springframework.beans.BeanUtils.copyProperties(BeanUtils.java:509)

Google took me to this bug which was already logged with SpringSource:

https://jira.springsource.org/browse/SPR-7693 (unfortunately it's still unfixed)

I made a quick fix/workaround for this.

Download/checkout : org.springframework.beans.BeanUtils.java

Add the below line after: writeMethod.invoke(target, value); (Around line 597) if using the 3.1 source.

if(logger.isDebugEnabled()){

logger.debug(MessageFormat.format("Source Property: {0}, Target Property:   {1}, Write method:{2}, Read Method {3} ", sourcePd.getName(),  targetPd.getName(), writeMethod.getName(), readMethod.getName()));

}

Add the file to your project. Now you can happily debug which property in the class is causing  problem.