Spring - geting system env variable in xml causes Null pointer Exception

Question

In my spring app, for database password, I have used

<property name="password" value="#{ systemProperties['password'] }" />

This throws null pointer Exception.
I am using windows 7, I had set the env variable though advanced settings option in system properties.
In cmd when I type echo %password% I get my password.

<bean id="dataSource" class="org.apache.tomcat.jdbc.pool.DataSource"> 
  <property name="driverClassName" value="com.mysql.jdbc.Driver" />
  <property name="url" value="jdbc:mysql://localhost:3306/test" />
  <property name="username" value="root" />
  <property name="password" value="#{ systemProperties['password'] }" />
</bean>

Error

SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in ServletContext resource [/WEB-INF/spring-servlet.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'password' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1453)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1158)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'password' threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:101)
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:57)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1450)
    ... 22 more

The problem looks more like with `systemProperties`. How is that getting defined? Are you using a properties placeholder of some sort? Why not just use the `${}` syntax? — chrylis -cautiouslyoptimistic-, Dec 17 '13 at 21:50
@chrylis It's predefined with SpEL. See [here](http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/expressions.html#expressions-beandef-xml-based). — Sotirios Delimanolis, Dec 17 '13 at 23:35
@SotiriosDelimanolis I'm going to be getting elbows-deep in the muck that is Acegi^HSpring Security. I really should read the whole SpEL chapter... — chrylis -cautiouslyoptimistic-, Dec 17 '13 at 23:52
Guarav, please post your setter for the `password` property. @chrylis I recommend Shiro instead of Spring Security. — Sotirios Delimanolis, Dec 17 '13 at 23:54
@SotiriosDelimanolis I've been waffling on the question for a new project. Your input? http://chat.stackoverflow.com/rooms/info/43387/spring-security-vs-shiro?tab=general — chrylis -cautiouslyoptimistic-, Dec 18 '13 at 03:49
@SotiriosDelimanolis I didn't used any setter for `password`. I have just initialized `password` as a system environment variable. — Gaurav Sharma, Dec 18 '13 at 11:42
No, I mean show us the class that contains the `password` property. — Sotirios Delimanolis, Dec 18 '13 at 13:39
@SotiriosDelimanolis the class with `password` property is the DataSource class from tomcat JDBC pool. I have updated it in my Question. — Gaurav Sharma, Dec 19 '13 at 05:59

Gaurav Sharma · Answer 1 · 2013-12-19T06:55:38.227

I used a Servlet Context Listener to initialize the java system property using

System.setProperty("password",System.getenv().get("password"));

This worked. Apparently #{ systemProperties['password'] } checks for java system property instead of system environment.
I am still looking for another way of solving it which would not require this Context Listener.

EDIT

Even This Worked

<property name="password" value="#{ T(java.lang.System).getenv().get('password') }" />

No need for servlet context

score 0 · Answer 2 · answered Dec 18 '13 at 00:10

0

This will work if you set your system property at the start-up of your JVM

java -Dpassword=mypasswd ...

Through Windows Advance setting options, you are only setting the environment variables, which are not accessible through System.getProperty, but through System.getEnv

answered Dec 18 '13 at 00:10

Biju Kunjummen

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I think Spring first checks `System.getProperty()` and if it returns `null`, checks `System.getenv()`. – Sotirios Delimanolis Dec 18 '13 at 04:07

Spring - geting system env variable in xml causes Null pointer Exception

2 Answers2