Debugging Tomcat-hosted applications running outside of Eclipse/WTP

1. Execute Tomcat like so:  <Tomcat home>/bin/catalina.sh jpda start
2. By default (see catalina.sh contents), the JPDA address is 8000
3. In Eclipse, set up the following under Run > Debug Configurations > Remote Java Application:
   
   
4. Of course, browse to the web application project you want to debug.  
5. When you run this debug configuration, you will be able to step-through the code just as if you were running the web application inside Eclipse/WTP.  If necessary, add more projects under the Source tab.
   

Testing REST-based web service over SSL using Jersey Client

To test a REST-based web service, I created a JUnit test that employs the Jersey client classes.  Once I changed the resource location to the https URL, I received the error "javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target".  At first, following the ideas on this Stack Overflow thread, I added some code to set up a ClientConfig with a SSLContext for the Jersey Client.  Then I created a new trust store with the server certificate (rather than importing into the default Java trust store) and pointed command-line arguments to this new trust store (and providing its password).  

However I continued to get the same error.  But when I imported the server certificate into the default Java trust store, the error went away.  And when I commented out all the ClientConfig code, and just used this.restWSClient = Client.create(); things continued to work!  It's possible I may not have referenced the new trust store properly but at this moment, it doesn't matter.  

One thing to note, SoapUI, which I previously used to test another web service over https on the same server, did not seem to require any client-side configuration (i.e. set up server certificate in trust store).  Not sure if it simply trusts whatever certificate that it sees. 

Configuring Axis2 to expose web services over https

1. First configure Tomcat to handle https.  This link is useful for this but note for development purposes,when the keytool prompts for “Common Name (CN)”, enter “localhost”
2. Without further configuration, if you attempt to access your web service over https, you will likely get an error about "https is forbidden" thrown from the AxisServlet class
3. Next, configure Axis2 to accept https calls.  Edit the axis2.xml configuration file.  There should already be a section that looks like:
   

       <transportReceiver name="http"
                          class="org.apache.axis2.transport.http.SimpleHTTPServer">
       <parameter name="port">8080</parameter>
   

   Add another section like this:
   

       <transportReceiver name="https"
                          class="org.apache.axis2.transport.http.SimpleHTTPServer">
           <parameter name="port">8443</parameter>
       </transportReceiver>
   

   (Port may vary depending on your Tomcat configuration)
4. Without further configuration, if you try again, you will probably get an error about java.lang.NoClassDefFoundError: org/apache/http/HttpResponseFactory.  This interface can be found in the httpcore library.  If using Maven, include the following in your POM file:
   

           <dependency>
               <groupId>org.apache.httpcomponents</groupId>
               <artifactId>httpcore</artifactId>
               <version>4.0</version>
               <scope>runtime</scope>
           </dependency>
   

5. Now it should be working as it did over regular http
   

Axis2 web service generation in Eclipse

Still exploring this but haven't figured out the purpose of two options in the Web Service wizard:

Not checking "Publish the Web service" still brings up a dialog about publishing to UDDI.  Not checking "Monitor the Web service" still creates a axis2-web folder and all the JSPs, etc. as checking the option; axis2-web seems to be a web application for monitoring the web service.

What effect do these options have? 

Strategies to creating a new web application project

A seemingly trivial task, starting a new web app project in Eclipse, requires specific steps when working with an assortment of technologies like Maven and Subversion.

1. File > New > Other > Dynamic Web Project 
2. To conform with Maven's WAR project structure, in the following dialog, specify /src/main/webapp for the Content Directory:

3. Once the project is created, right-click on project > Maven > Enable Dependency Management. 
4. The project can be associated with a pre-existing Subversion folder by Team > Share Project and on this dialog, enter the path of the Subversion folder at "Use specified folder name":
 
5. I might have been on crack when I performed the steps below ... they are not necessary and are retained only for reference purposes:
   
6. If you generally set-up a project in Subversion with the typical folders of branches, tags, trunk, create these first and then with Subclipse check-out the trunk as your working copy (change the project name from trunk to something appropriate).  If you start your project in Eclipse and then attempt to Team > Share Project, Eclipse dialogs seem to force you to create a new Subversion location under trunk rather than committing to trunk directly
7. Create Maven web app project, commit, re-check-out using Eclipse New Project Wizard 
1. Use a Maven archetype to create the skeleton of your web app project in the SVN working copy.  You can do this from the command-line (refresh workspace once done) or using m2eclipse via File > New > Other > Maven project.  However this step does not create an Eclipse project that is recognized by WTP's Tomcat
2. Commit Maven project
3. Then delete project from workspace including contents on disk (this is OK since everything is already committed to Subversion)
4. Re-check-out using Eclipse's New Project Wizard, choosing Dynamic Web Project for the wizard type.  Along the way, there is a dialog box that asks for "Content directory":  From here you cannot specify the webapp directory in Maven's specific structure so just ignore for now
5. Once the project is checked-out, edit the file .settings/org.eclipse.wst.common.component.xml  There is a line that will probably read <wb-resource deploy-path="/" source-path="/WebContent"/>.  Change that to <wb-resource deploy-path="/" source-path="/src/main/webapp"/>
6. Your project should now be Add-able to WTP's Tomcat and content in /src/main/webapp should be viewable in the web browser

Subversion over SSH on Windows: Folder '' does not exist remotely

Setting up SpringSource Tool Suite on Windows 7, when attempting to connect using Subclipse to SVN server with a URL of the form svn+ssh://, get the error "Folder '' does not exist remotely". 

Some people have had luck with HowTo: Configure SVN+SSH with Subclipse on Windows but I kept being prompted for username/password with each folder navigation in the SVN repository (unworkable!).  One of the comments in the blog referred me to Subversion Access from Eclipse Using Subclipse which worked for me although I continue to use username/password (saved) rather than public/private key as the latter method didn't work.  I probably have the key saved improperly on the client and/or server side. 

Other problems that I had as I accessed our SVN server over a VPN:

• hostname wasn't resolving so I had to find out the IP address of the SVN server and use that in the URL
• Attempted to use TortoiseSVN as it supposedly handles svn+ssh:// out of the box but after installation and rebooting Windows, still couldn't find the TortoiseSVN menu in the context menu in Windows Explorer

Re-using your code with Perl modules

Re-use of code, when not copying-and-pasting, is a good thing.  I consider myself beyond a novice Perl programmer.  But since it was never a primary tool at work, I never learned how to develop re-usable Perl modules properly.  Following is a bare-bones implementation of a Perl module.  Note that a module containing a Perl class implementation would not have to use Exporter (nor should it!)

#!/usr/bin/perl
use strict;
use warnings;

package MyPkg;

require Exporter;

our @ISA = qw(Exporter);
our @EXPORT_OK = qw(myfunc);


sub myfunc{ 
 print "bar";
}


1;

In this case, the file containing this code should be named MyPkg.pm, to match the name of the package.  A bare-bones caller of this code could be as simple as:

 

#!/usr/bin/perl
use strict;
use warnings;

use MyPkg qw{myfunc};

myfunc();

Some additional notes:

• In the module, require Exporter; is not always necessary (not yet clear the situation for its necessity)
• If your package is something like MyGroup::MySubGroup, two things to observe:  (1) the name of your .pm file should be MySubGroup.pm and (2) the file should be placed in a subdirectory relative to @INC paths named MyGroup.  For example, if you want to locate your re-usable module togehter with your Perl script, you would put it in a subdirectory of the directory with the Perl script named MyGroup

Tomcat installation changed, problems launching Tomcat in Eclipse

• Install location of Tomcat has changed.  Get message "The archive: [...]/apache-tomcat-6.0.20/bin/bootstrap.jar which is referenced by the classpath, does not exist." when attempting to launch Tomcat in Eclipse
• Fix: 
1. In Servers view, double-click on Tomcat server.  Overview of Tomcat settings appears.  
2. Click on "Open launch configuration"
3. Go to Classpath tab
4. Edit User Entries as appropriate
• If you haven't already, specify your Tomcat installation under Preferences > Server > Runtime Environments

Compiling PL/SQL and using TOAD to write stored procedures

• PL/SQL compiler (version?) is quite stupid:  Missing a semi-colon flags a line several lines below where the actual semi-colon is missing.  Likewise for a missing single quote character
• To escape the single quote character, double it.  Therefore four consecutive single quotes is a string consisting of a single quote
• When the compiler reports a compiler error at a certain line, that line # is relative to the start of the Body of stored procedure (assuming you are editing the Body and not the Spec)
• To compile and "save" your stored procedure to the Oracle server in TOAD, be sure to use the "Execute As Script" button () in the Editor.  Do NOT use the "Execute/compile statement at caret" button.
• In order to see debug output (i.e. from DBMS_OUTPUT.PUT_LINE function):  Where does DBMS_OUTPUT.PUT_LINE() output go (in Toad) ?

Getting TOAD running without tnsnames.ora, etc.

1. Download/install TOAD
2. Download/install Oracle Instant Client
3. Know your database server's Host IP, Port number, and SID for desired database
4. When you attempt to connect using TOAD, fill in the "Direct" tab with the information from previous step and select to connect using Instant Client (may already be the default)

Additional note:  Although I am using 64-bit Windows 7, the 64-bit version of the Instant Client did not appear to work (an error about "unable to load oci.dll" within TOAD).  However, the 32-bit version worked fine.

Jersey, JAX-RS notes on Jersey 1.3 User Guide

• Jersey 1.3 User Guide
• a more detailed document than the "RESTful Web Services Developer's Guide", especially regarding JSON support and the Jersey client API 
• example of "Builder" pattern utilized by Jersey client API, rather than the JavaBean get/set pattern:
  
  

  8   JAXBBean bean = r.
  9     type(MediaType.APPLICATION_FORM_URLENCODED_TYPE)
  10    .accept(MediaType.APPLICATION_JSON_TYPE)
  11    .post(JAXBBean.class, f);
  

Jersey, JAX-RS notes for RESTful Web Services Developer's Guide

• RESTful Web Services Developer's Guide
• can embed variables in the URIs. URI path templates are URIs with variables embedded within the URI syntax
• "A fundamental part of REST is that the next set of valid operations is encoded in the response from the last. This means that as long as you only use actions from the last operation you will always perform a valid operation according to the application protocol." - does this feature exist in Jersey?
• "If a character in the value of a variable would conflict with the reserved characters of a URI, the conflicting character should be substituted with percent encoding." - use case?
• If the application needs to supply additional metadata, such as HTTP headers or a different status code, a method can return a Response that wraps the entity, and which can be built using Response.ResponseBuilder.
• By default, a resource class can respond to and produce all MIME media types of representations specified in the HTTP request and response headers
  
  
  

Free TOAD versus SQuirreL SQL Client

One of the things that require me to use Windows is the lack of availability of TOAD on Linux.  I am evaluating the Java tool Squirrel SQL Client to see how it stacks up for Oracle development:

	Free TOAD	SQuirreL SQL Client
DDL	The Script tab shows referential integrity constraints, comments on columns, in addition to the usual CREATE TABLE DDL	Evaluating ...
Auto-completion of SQL	Doesn't work with usual Ctrl+space keyboard short-cut	Works well
"Bookmark favorite" tables	Evaluating ...	Evaluating ...
DDL	The Script tab shows referential integrity constraints, comments on columns, in addition to the usual CREATE TABLE DDL	Evaluating ...
<placeholder>	<placeholder>	<placeholder>

Getting comments on Oracle tables

If your Oracle tool doesn't support pulling the comments for tables you are accessing, try this SQL:

select COLUMN_NAME, COMMENTS
from ALL_COL_COMMENTS
where TABLE_NAME =