You can see this post http://jforum.andowson.com/posts/list/16.page as the first step.
Modify the css file and header.htm can do most of the work.

Please check your web container's log file(for example, Tomcat's catalina.out)
And see if there are some error messages as a hint for what's going wrong there.
Also, you'd better provide some environment information like OS version, Java version, etc.

Since JForum use JCaptcha as the capacha engine, you can check the FAQ on JCaptcha project website.
For Example, if you're running JForum on Linux server, you have to set the option in your JAVA_OPTS

-Djava.awt.headless=true

BTW, JForum 2.3.5 is not secure, you'd better install JForum 2.4.0 or later.

Secure Network releases the security advisory SN-15-01 for multiple vulnerabilities found in JForum.

SN-15-01: multiple vulnerabilities have been identified in JForum version 2.1.9 stable and its unofficial updated version 2.3.5, ranging from high-impact issues like Stored Cross-Site Scripting (XSS) and Remote Code Execution (RCE) to lower-impact ones like missing security flag for session cookie. Older versions may also be vulnerable.

Source URL:
https://www.securenetwork.it/en/research/advisories/2015/02/sn-15-01/

Please update to JForum version 2.4.0 or later.

All right, finally, I did download and install NetBeans IDE and build JForum with NetBeans IDE.
I checkout the latest source code from svn trunk, and without modifing any code, I can build JForum successfully.
So I suggest you clean up your workspace and download from svn again.

JForum 2.3.x and later uses maven as build tool, you can follow the maven directory structure and find the two files under /src/main/webapp
http://jforum2.googlecode.com/svn/trunk/src/main/webapp/

This URL maybe help for usgin Maven in NetBeans:
https://netbeans.org/kb/docs/javaee/maven-entapp.html

Hi, sorry that JForum 2.4.0 can't be compiled with JDK8 right now.
JDK8 introduces many new features and deprecates some methods, this will cause a lot of conversion work.
And we keep the minimum system requirement of Java 6.
I'd suggest you switch back to JDK 7 for compile JForum 2.3.x or 2.4.x.
Your days will be much happier.

BTW, I use eclipse to build JForum, so I don't have the source code for NetBeans. And all source code is published on googlecode svn.

Sorry, are you using JDK8? Try switching to build with JDK7 and add back that methods.
BTW, version 2.4.x is more secure than any previous version, so you can also download the latest code from SVN trunk.

If you put Tomcat behind Apache HTTPD Server, then you can use Apache's rewrite module with some rewrite rule like the following in httpd.conf:

RewriteRule ^/posts/list/t/([1-9]+[0-9]*)/(.*)$ /posts/list/$1.page [P]

Notice that /posts/list/t/ prefix is used to distinguish from normal url ended with .page
And you can use the syntax to create it in freemarker template

/posts/list/t/${topic.topicId}/${topic.topicTitle?html}

For example:
http://jforum.andowson.com/posts/list/t/114/JForum 2.4.0 released

Or you can shorten the prefix from /posts/list/t/ to /t/ only

RewriteRule ^/t/([1-9]+[0-9]*)/(.*)$ /posts/list/$1.page [P]

And you can use the syntax to create it in freemarker template

/t/${topic.topicId}/${topic.topicTitle?html}

For example:
http://jforum.andowson.com/t/114/JForum 2.4.0 released

Please remove that method getParameterNames() from WebRequestContext.java, and build it again.

The JForum2 Project is proud to announce the release of version 2.4.0 of JForum. This release includes bug fixes and new features compared to version 2.3.5.

You can download the latest war file from the following URL, then deploy it to your Tomcat's webapps directory:
http://sourceforge.net/projects/jforum2/files/jforum-2.4.0.war/download
If your Tomcat doesn't unpack the war file automatically, you'll need to unpack it manually, then restart your Tomcat.

Please remove that method getParameterNames() from WebRequestContext.java, and build it again.

Hi, welcome to the community.
Please check your web container's log file(for example, Tomcat's catalina.out)
And see if there are some error messages as a hint for what's going wrong there.
Also, you'd better provide some environment information like OS version, Java version, etc.

It looks like I18n, so I guess you can put it in the prepareTemplateContext() method of ControllerUtils.java:
[code=java;first-line:91]public void prepareTemplateContext(final SimpleHash context, final ForumContext jforumContext)
{
...
context.put("I18n", I18n.getInstance());
...
context.put("TokenGenerator", TokenGenerator.getInstance());
...
}[/code]

Thank you for remind me. I have added a tag v2.3.5 now. It's based on r306.

I fixed the post_form.htm, the code should be as follows(for JForum 2.3.5):

<select onmouseover="helpline('s')" onchange="bbfontstyle('[color=' + this.form.addbbcode30.options[this.form.addbbcode30.selectedIndex].value + ']', '[/color]')" name="addbbcode30">

<select onmouseover="helpline('f')" onchange="bbfontstyle('[size=' + this.form.addbbcode32.options[this.form.addbbcode32.selectedIndex].value + ']', '[/size]')" name="addbbcode32">

now the color and font should work as expected