Kesha Williams, certified professional and software developer, explores the imbalance of diversity in the world of technology -- especially when it comes to hiring women. She showcases ways she's making a difference through the Colors of STEM program.
refactoring java code
Hi,
Following is my main function :
I want to know experts comment on this. If i can improve it in some way..
Some things that probably can be changed are :
1) I am assigning int port = 0
which actually does not make any sense as i want the port to be read from a file and if i cannot read it
applications stops.
2) there is one try catch block and one try finally
Is this code fine or there is some improvement scope in it ?
Thanks
Following is my main function :
public static void main(String[] args) throws Exception {
String env = System.getProperty("FLOCK_APPS_CONFIG");
int port=0;
try {
InputStream in = new FileInputStream(env);
Properties props = new Properties();
props.load(in);
PropertyConfigurator.configure(props);
port = Integer.parseInt(props.getProperty("port"));
}
catch (Exception e)
{
logger.log(Level.SEVERE,"Error accessing config File : "+env,e);
System.exit(1);
}
AppStart appStart = new AppStart(port);
try {
appStart.start();
appStart.waitForInterrupt();
} finally {
appStart.stop();
}
System.exit(1);
}
I want to know experts comment on this. If i can improve it in some way..
Some things that probably can be changed are :
1) I am assigning int port = 0
which actually does not make any sense as i want the port to be read from a file and if i cannot read it
applications stops.
2) there is one try catch block and one try finally
Is this code fine or there is some improvement scope in it ?
Thanks
Do more with
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
props.load(in);
logger.log(Level.SEVERE,"Error accessing config File : "+env,e);
You should log.debug the port you read
Why do you use exit code 1 finally?
If you structure your code and its exception handling you won't have to use that first System.exit as a kludgy GOTO
Hi,
reason for using Exit code 1 is, In one of the cases i got the following exception and the application shutdown :
And i got the following output in console of Intellij Idea :
Process finished with exit code 0
Which i think is incorrect as the application shutdown abruptly due to some database error. So i am returning exit code 1 as to signify that there was something wrong.
Please let me know your views on this.
reason for using Exit code 1 is, In one of the cases i got the following exception and the application shutdown :
2015-11-26 13:33:30 ERROR main org.directi.code.dao.SnippetDaoImpl Error querying Database after Initialization :
org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:390)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:470)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:480)
at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:490)
at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:496)
at org.directi.code.dao.SnippetDaoImpl.afterPropertiesSet(SnippetDaoImpl.java:55)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1145)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1069)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:967)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:543)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:834)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:667)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:633)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:681)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:552)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:493)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
at javax.servlet.GenericServlet.init(GenericServlet.java:244)
at org.eclipse.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:626)
at org.eclipse.jetty.servlet.ServletHolder.initialize(ServletHolder.java:405)
at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:875)
at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:346)
at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1380)
at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1342)
at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:772)
at org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:259)
at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:518)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
at org.eclipse.jetty.server.Server.start(Server.java:405)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:106)
at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:61)
at org.eclipse.jetty.server.Server.doStart(Server.java:372)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.directi.code.AppStart.start(AppStart.java:70)
at org.directi.code.AppStart.main(AppStart.java:47)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)
at org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1549)
at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1388)
at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
... 60 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:400)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1038)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:339)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2247)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2280)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2079)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:400)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582)
at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:1556)
at org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1545)
... 64 more
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:214)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:298)
... 80 more
And i got the following output in console of Intellij Idea :
Process finished with exit code 0
Which i think is incorrect as the application shutdown abruptly due to some database error. So i am returning exit code 1 as to signify that there was something wrong.
Please let me know your views on this.
ALso you mentioned :
If you structure your code and its exception handling you won't have to use that first System.exit as a kludgy GOTO
You mean i can avoid the first System.exit in my code ?
Please give some more pointers...
As there are two things going on here :
1) reading a config file -- which can break due to wrong parameters in it/ the file location itself is wrong
2) server startup embedded jetty --- this can go wrong due to wrong database configuration, port number busy etc..
If you structure your code and its exception handling you won't have to use that first System.exit as a kludgy GOTO
You mean i can avoid the first System.exit in my code ?
Please give some more pointers...
As there are two things going on here :
1) reading a config file -- which can break due to wrong parameters in it/ the file location itself is wrong
2) server startup embedded jetty --- this can go wrong due to wrong database configuration, port number busy etc..
The point is that you need to inspect each line of your code for possible errors, the exceptions than can be thrown and suitable ways of logging them and maybe dealing with them.
e.g if someone put in the value "80x" for key "port" in your code, your log file would tell them that there was a problem accessing the config file. Wrong!
e.g if someone put in the value "80x" for key "port" in your code, your log file would tell them that there was a problem accessing the config file. Wrong!
Premium Content
You need an Expert Office subscription to comment.Start Free Trial