Hello Guys

Many times we are getting NullPointerException in our liferay server log during upload, upadte and delete files.

Error look like as below in our server log :

20:22:50,828 INFO  [liferay/search_writer/SYSTEM_ENGINE-3][BaseSpellCheckIndexWriter:255] Start indexing dictionary for com/liferay/portal/search/lucene/dependencies/spellchecker/en_US.txt
20:22:50,829 WARN  [liferay/search_writer/GENERIC_ENGINE-1][ProxyMessageListener:81] java.lang.NullPointerException
java.lang.NullPointerException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.liferay.portal.kernel.messaging.proxy.ProxyRequest.execute(ProxyRequest.java:85)
        at com.liferay.portal.kernel.messaging.proxy.ProxyMessageListener.receive(ProxyMessageListener.java:51)
        at com.liferay.portal.kernel.messaging.InvokerMessageListener.receive(InvokerMessageListener.java:72)
        at com.liferay.portal.kernel.messaging.ParallelDestination$1.run(ParallelDestination.java:69)
        at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask._runTask(ThreadPoolExecutor.java:682)
        at com.liferay.portal.kernel.concurrent.ThreadPoolExecutor$WorkerTask.run(ThreadPoolExecutor.java:593)
        at java.lang.Thread.run(Thread.java:662)

I have resovled this issue, Please follow below steps :

Step 1: Download apache-solr-4.0.0.zip from 'http://archive.apache.org/dist/lucene/solr/4.0.0/' website.

Step 2: Unzip apache-solr-4.0.0.zip to an folder.

Step 3: Navigate to apache-solr-4.0.0/example in terminal and type 'java -jar start.jar'

Step 4: After the server has started up, shut it down.

Step 5: Start Liferay server and deploy the Solr4 plugin.

Step 6: After Liferay server started, shut it down.

Step 7: Navigate in folder to /tomcat-7.0.42/webapps/solr4-web/WEB-INF/classes/META-INF

Step 8: Open solr-spring.xml file.

Step 9: Change 'http://localhost:8080/solr' to 'http://localhost:8983/solr'

Step 10: The changed line should look like this:

<constructor-arg type="java.lang.String" value="http://localhost:8983/solr/">

Step 11: Save and close solr-spring.xml

Step 12: Navigate in folder to /tomcat-7.0.42/webapps/solr4-web/WEB-INF/conf

Step 13: Open the schema.xml file and do a find for 'version'

Step 14: If it does not have it, then add

<field indexed="true" multivalued="false" name="version" stored="true" type="string"/> 
after a <dynamicfield indexed="" ..=""/>

Step 15: Save and close the file

Step 16: Copy the schema.xml file

Step 17: Paste the file in apache-solr-4.0.0/example/solr/collection1/conf to replace the existing schema.xml file.

Step 18: Start the Solr4 server in apache-solr-4.0.0/example (java -jar start.jar)

Step 19: Start liferay server

Step 20: There will be a lot of output on the Solr4 console (means it's working)

Step 21: Navigate to Control Panel > Server Administration and reindex the spellcheck indexes