47. What is the error HTTP 404 indicates and how to solve these issues?
This error might be because of Application server non availability. Need to check the logs and server status then need to take appropriate action to resolve the issue.
48. What is the difference between page not found and HTTP 404? How to solve these issues?
The “Page not found” error is, the request is not reaching the server. HTTP 404 errors is request is reaching to server but whatever it is expecting it’s not found at expected location
49. What is meant by ear expander utility?
EAR Expander utility is used to expand the application binaries into any path, normally we will use this to expand it in other than the default path.
Once expanded we will update the same app binaries from WAS admin console to update WAS.
The EAR Expander expands Ear files into the format desired by the application server runtime, as described in the application installation instructions. EAR Expander can also collapse the expanded format back to a normal Ear (.jar or .zip) format.
Invoking the tool
The tool is located in the following directory:
product_installation_root/bin/EARExpander.bat
To view syntax, open a command line and invoke the tool without arguments. Here is a typical result. The line breaks have been changed for better formatting in this documentation.
C:\seaa0122.02\bin>EARExpander.bat IBM WebSphere Application Server,
Release 4.0 J2EE
J2EE Application Expansion Tool, Version 1.0
Copyright IBM Corp., 1997-2001
Required Argument Missing: ear
Usage: java com.ibm.websphere.install.commands.EARExpander
-ear -expandDir -operation [expansionFlags]
ExpansionFlags indicate whether you want every JAR file expanded, or just the contained WAR files within the EAR file. The default is all.
Expanding files
The following example command expands the file my.ear into the product_installation_root/bin/myEAR directory:
EARExpander -ear my.ear -expandDir product_installation_root/bin/myEAR
-operation expand
Collapsing files
Using the collapse -operation reverses the format to normal.
EARExpander -ear my.ear -expandDir product_installation_root/bin/myEAR
-operation collapse
Type each of the above commands on a single line, despite their appearance in this documentation.
50. What is meant by JAVA Script?
Java script is a scripting tool to developed web applications.
51. What is meant by Heap in Java process and what information will be available in heap file?
Heap is used to collect the garbage for java applications; the Heap file contains the garbage collected from java process.
52. What are the available log file in the WAS 6.1
In was there are list of logs available to monitor and troubleshoot. They are
Diagnostic Trace Service
View and modify the properties of the diagnostic trace service. Diagnostic trace provides detailed information about the execution of Websphere Application Server components within this managed process. Changes on the Configuration panel will apply when the server is restarted. Changes on the Runtime panel will apply immediately.
“IT provides detailed information about the execution of web sphere application server components with in the managed process.”
JVM Logs
View and modify the settings for the Java Virtual Machine (JVM) System.out and System.err logs for this managed process. The JVM logs are created by redirecting the System.out and System.err streams of the JVM to independent log files. “The System.out log is used to monitor the health of the running application server”. “The System. err log contains exception stack trace information that is useful when performing problem analysis”. There is one set of JVM logs for each application server and all of its applications. JVM logs are also created for the deployment manager and each node manager. Changes on the Configuration panel will apply when the server is restarted. Changes on the Runtime panel will apply immediately.
Process Logs
View or modify settings for specifying the files to which standard out and standard error streams write. The process logs are created by redirecting the standard out and standard error streams of a process to independent log files. Native code writes to the process logs. These logs can also contain information relating to problems in native code or diagnostic information written by the JVM. There is one set of process logs for each application server and all of its applications. Process logs are also created for the deployment manager and each node manager. Changes on the Configuration panel will apply when the server is restarted. Changes on the Runtime panel will apply immediately.
native_stdout.log and native_stderr.log are usually blank. Their function is unknown at this time. Enabling verbose garbage collection logging is often required when tuning and debugging many issues. The verbose garbage collection output is written to either native_stderr.log or native_stdout.log or the Application Server depending on the SDK operating system as follows:
native_stderr.log --- AIX, MS Windows, Linux
native_stdout.log --- Solaris, HP-UX
native_stdout.log --- Solaris, HP-UX
IBM Service Logs
Configure the IBM service log, also known as the activity log. The IBM service log contains both the WebSphere Application Server messages that are written to the System.out stream and some special messages that contain extended service information that can be important when analyzing problems. There is one service log for all WebSphere Application Server Java virtual machines (JVMs) on a node, including all application servers. and their node agent (if present). A separate activity log is created for a deployment manager in its own logs directory. The IBM Service log is maintained in a binary format. Use the Log Analyzer or Showlog tool to view the IBM service log.
Change Log Detail Levels
Log levels allow you to control which events are processed by Java logging. Click Components to specify a log detail level for individual components, or Groups to specify a log detail level for a predefined group of components. Click a component or group name to select a log detail level. Log detail levels are cumulative; a level near the top of the list includes all levels below it.
53. If a developer requests to tune an application then what you will do?
All the steps for Performance Tuning would approximately take 45 minutes.
JVM Heap Size
By default, the Java virtual machines for WebSphere Application Server and WebSphere Portal Server are assigned only 256 MB per process. This value should be increased.
To change this value, open the WebSphere Admin Console and go to
Servers -> Application Servers -> (all server names) -> Process Definition -> Java Virtual Machine
and set both initial heap size and max heap size to an adequate value:
on a machine with 4 GByte of real memory, set it to 1024 MByte, on a 8 GByte machine to 2048 MByte.
If a value greater than 1024 MByte is selected, it may be necessary to change the AIX parameter LDR_CONTRL. For details, please refer to the AIX documentation.
Session Timeout
Reducing the session timeout can help reduce memory consumption requirements.
To change this value, open the WebSphere Admin Console and go to
Servers -> Application Servers -> (all server names) -> Web Container -> Session Management -> Session Timeout
and set Timeout to 10 Minutes.
Class Garbage Collection
To change this value, open the WebSphere Admin Console and go to
Servers -> Application Servers -> (all server names) -> Process Definition -> Java Virtual Machine -> Generic JVM arguments
and add the parameter -Xnoclassgc.
Servlet Engine Thread Pool Size
To change this value, open the WebSphere Admin Console and go to
Servers -> Application Servers -> (all server names) -> Web Container -> Thread Pool
and add the parameters for Minimum size threads and Maximum size threads to 70.
Data Source Connection Pool Size
To change this value, open the WebSphere Admin Console and go to
Resources -> JDBC Providers -> (all providers) -> Data Sources -> (all data sources) -> Connection Pools
and set the parameters for Minimum connections and Maximum connections to 50.
Statement Cache Size
To change this value, open the WebSphere Admin Console and go to
Resources -> JDBC Providers -> (all providers) -> Data Sources -> (all data sources)
And set the parameter for Statement Cache Size to 500.
54. Tell about Resource analyser?
Resource analyser is used to analyse the performance of the WAS resources. It is a monitoring tool comes with WAS.
55. Tell about data source?
Installed applications use JDBC providers to interact with relational databases. The JDBC provider object supplies the specific JDBC driver implementation class for access to a specific vendor database. To create a pool of connections to that database, you associate a data source with the JDBC provider. Together, the JDBC provider and the data source objects are functionally equivalent to the J2EE Connector Architecture (JCA) connection factory, which provides connectivity with a non-relational database.
Data sources allow you to manage a pool of connections to a database
Data sources work as follows:
When a client wants to use a connection, it looks up a data source by name from a JNDI server.
The data source then returns a connection to the client.
If the data source has no more connections, it may ask the database manager for more connections (as long as it has not exceeded the maximum number of connections).
When the client has finished with the connection, it closes the connection.
The data source then returns the connection to the available pool.
You can configure data sources for WebSphere® Application Server v6.x by using the Deployment page in the application deployment descriptor editor or using the administrative console. For WebSphere Application Server v5.11 test environments and servers you can configure data sources by using the Data Source page in the server editor.
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