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NullPointerException

 
Greenhorn
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Good afternoon,
I have a problem this nullpointerexception please help.......


HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
root cause

java.lang.NullPointerException
org.apache.jsp.home_jsp._jspService(home_jsp.java:172)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.27 logs.
 
Rancher
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Your home.jsp threw a NullPointerException somewhere.
 
Ranch Hand
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Go through your code and check that all your objects have been instantiated .



will cause a nullpointer exception.

So go through your code on the offending JSP and check that each object has been instantiated



if its a method call creating the object make sure the object has been instantiated in that method.
 
kasa spandana
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kasa spandana
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In home.jsp we have another jsp pages then how can i resolve that problem???
 
Bartender
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Please UseCodeTags <--- (click). I added them for you this time. See how much easier it is to read? But your line lengths are still too long and your indentation is all over the place. That makes it difficult for others to read your code.

What IDE are you using? There is usually a simple key combination that will adjust all the indentation and a setup screen where you can set the maximum line length. We can tell you how to find them.

And welcome to the Ranch!
 
Bartender
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Using scriptlet tags in a JSP page: -20
Writing SQL code in a JSP page: -50
Having SQL Injection in said SQL code: -100
Using an HTML marquee tag ...


Java code belongs in a java class. Not a JSP page.
The standard technique is to use a servlet to run database code, execute sql, put any results required by the JSP page into a request attribute and then forward to said JSP page.

At a guess, the null pointer is the combinatin of these two lines:


Integer count = (Integer) application.getAttribute("pcount");
<%=count++%>


What happens when the attribute is not declared?
 
kasa spandana
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Good morning everyone,
there is no error in my project but after running it is showing following error.Please help me.......

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
root cause

java.lang.NullPointerException
org.apache.jsp.home_jsp._jspService(home_jsp.java:172)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.27 logs.
 
kasa spandana
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Bartender,
whatever you said is correct it shows error at count++ but i have checked in database table it is having some value then why it shows null pointer exception i don't know please help me friends.
 
Dave Tolls
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This is one of the key reasons for not putting Java code into a JSP page.
It is a pain to debug.

If all that stuff was in separate classes, and a model built in a Servlet for display by the JSP, then you could test it out properly.

As it stands do you even know which bit of your code is causing the NPE?
I don't...
 
Sheriff
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Exactly, step 1 is to refactor your code to remove all Java code form the JSP. That's a bad practice that has been discredited and obsolete for 14 years!
 
kasa spandana
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Friends,
whatever you said i con't understand please explain in detail please......
 
Dave Tolls
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kasa spandana wrote:Friends,
whatever you said i con't understand please explain in detail please......



Put simply, don't so this:

in a JSP.
You shouldn't have any Java code in a JSP as it's a pain to debug (as you are seeing).
The general flow should be, the client browser sends a request to the server. This is handled by a Servlet. The Servlet processes the request, gathering the data together for whatever should be sent back to the client. It then forwards to a JSP to handle the display of the data.

That way you can actually debug code like the bit above.
 
Bear Bibeault
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Please read this article to understand how to structure modern Java web applications.

You might also want to read this article.
 
Ranch Hand
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"The full stack trace of the root cause is available in the Apache Tomcat/7.0.27 logs. "

Have you checked the full stack trace?
 
kasa spandana
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While running project it shows following error in Apache Tomcat log

Apache Tomcat 7.0.27.0 log:

SEVERE: Servlet.service() for servlet [jsp] in context with path [/apsointranet] threw exception [java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at org.apache.jsp.home_jsp._jspService(home_jsp.java:172)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)

Apache Tomcat 7.0.27.0:


Using CATALINA_BASE: "C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base"
Using CATALINA_HOME: "C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.27"
Using CATALINA_TMPDIR: "C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base\temp"
Using JRE_HOME: "C:\Program Files\Java\jdk1.7.0_75"
Using CLASSPATH: "C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.27\bin\bootstrap.jar;C:\Program Files\Apache Software Foundation\Apache Tomcat 7.0.27\bin\tomcat-juli.jar"
Mar 23, 2015 12:28:06 PM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jdk1.7.0_75\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\oraclexe\app\oracle\product\10.2.0\server\bin;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Client\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x86;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x64;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x86;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x64;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Microsoft\Web Platform Installer\;C:\Program Files\Java\jdk1.7.0_71\bin;.;;.
Mar 23, 2015 12:28:09 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8084"]
Mar 23, 2015 12:28:09 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
Mar 23, 2015 12:28:09 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 3310 ms
Mar 23, 2015 12:28:09 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Mar 23, 2015 12:28:09 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.27
Mar 23, 2015 12:28:09 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base\conf\Catalina\localhost\apsointranet.xml
java.sql.SQLException: [Microsoft][ODBC Driver Manager] The specified DSN contains an architecture mismatch between the Driver and Application
at sun.jdbc.odbc.JdbcOdbc.createSQLException(JdbcOdbc.java:6964)
at sun.jdbc.odbc.JdbcOdbc.standardError(JdbcOdbc.java:7121)
at sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(JdbcOdbc.java:3080)
at sun.jdbc.odbc.JdbcOdbcConnection.initialize(JdbcOdbcConnection.java:323)
at sun.jdbc.odbc.JdbcOdbcDriver.connect(JdbcOdbcDriver.java:174)
at java.sql.DriverManager.getConnection(DriverManager.java:571)
at java.sql.DriverManager.getConnection(DriverManager.java:233)
at MyCounter.contextInitialized(MyCounter.java:33)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4779)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5273)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:649)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1585)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Mar 23, 2015 12:28:12 PM org.apache.catalina.util.SessionIdGenerator createSecureRandom
INFO: Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [149] milliseconds.
Mar 23, 2015 12:28:12 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base\conf\Catalina\localhost\manager.xml
Mar 23, 2015 12:28:12 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base\conf\Catalina\localhost\ROOT.xml
Mar 23, 2015 12:28:12 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base\conf\Catalina\localhost\WebApplication1.xml
Mar 23, 2015 12:28:13 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Users\Administrator\AppData\Roaming\NetBeans\7.2\apache-tomcat-7.0.27.0_base\conf\Catalina\localhost\WebApplication7.xml
Mar 23, 2015 12:28:13 PM org.apache.catalina.core.StandardContext resourcesStart
SEVERE: Error starting static Resources
java.lang.IllegalArgumentException: Document base C:\Users\Administrator\Documents\NetBeansProjects\WebApplication7\build\web does not exist or is not a readable directory
at org.apache.naming.resources.FileDirContext.setDocBase(FileDirContext.java:140)
at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4894)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5074)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:649)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1585)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

Mar 23, 2015 12:28:13 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Error in resourceStart()
Mar 23, 2015 12:28:13 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Error getConfigured
Mar 23, 2015 12:28:13 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/WebApplication7] startup failed due to previous errors
Mar 23, 2015 12:28:13 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8084"]
Mar 23, 2015 12:28:13 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
Mar 23, 2015 12:28:13 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 4184 ms


 
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