The search phrases sap platin-gui freezes and use sapgui for java frequently appear in my server log files. However, as I used these in a different context, people will be disappointed once they discover that there are no articles concerning SAP GUI for Java except an installation guide for FreeBSD. This is obviously a matter of some importance, judging from the page hits, so I decided to do my part in the great struggle for bug-free software.

Using SAP GUI for Java

Let me answer the second search string first: Yes, you should use SAP GUI for Java. It is stable, secure and fast. SAP only lists a fraction of all Linux distributions in their Lifetime and Support Matrix for SAP GUI for Java. This is to ensure the highest standards of quality (in translation: SAP does not want to get sued into oblivion and must check that it really, really works at least with some operating systems. It not easy, given the myriad of system environments out there in the wild).

However, in almost all cases, SAP GUI for Java should run just fine under your personal Linux distribution of choice. So, on to the installation:

1. Download a recent Java Runtime Environment from Sun.
2. Download a recent version of SAP GUI for Java. Pick the jar-file that fits your operating system best.
3. Start the installation via java -jar PlatinGUI-Linux-710r9.jar (or execute the jar-file using another method of your choice).

You are done.

Solving problems with SAP GUI for Java

There are several things to do when the GUI freezes or hangs.

• Execute SAP GUI for Java from a terminal emulator. Use xterm or the likes. This allows you to view any error messages that might help to pinpoint problems within the source code.
• Try a different Java Runtime Environment. Install an older JRE (there is no need to remove the current one). Set the PLATIN_JAVA environment variable to the installation directory of the older JRE, for example by executing export PLATIN_JAVA=/usr/local/Java/jre1.6.0_11/bin/java and /opt/SAPClients/SAPGUI710rev9/bin/guilogon from a terminal.
• Try a different version of SAP GUI for Java. It is possible to install different versions in parallel. I would recommend this option especially if you are testing a new version for deployment.
• Check with a supported operating system. Take a look at the Lifetime and Support Matrix for SAP GUI for Java and set up a test environment. This should be your last resort, because in most cases, the problem does not depend on your operating system.
• Take a stack trace. If the GUI hangs, follow this very helpful article and create a stack trace. This diagnostical information is very helpful for SAP's support teams.

Reporting problems

In any case: You should always report your problems. SAP is very grateful for any feedback, even if it is in the form of debug information. You can use one of the following means of communication:

• Use the SDN Expert Forums (free registration required, section "Application Server—SAP GUI", for lesser problems, general questions or if you do not have an account for the SAP Service Marketplace.
• Create a bug report at SAP. Use BC-FES-JAV as the component.

Whatever you do, try to describe the problem as precisely as possible: Attach all debug information (stack traces, error messages etc.) and create a step-by-step reproduction scenario. The more information you provide, the less time your request will take.

This is, for example, a bad bug report:

hello, i get error in gui. please advise!

Whereas this is definitely better (of course, a step-by-step description would be best. System information is also not included, but at least, one could try to reproduce the problem now):

When I click the "delete world" button in transaction GOD, SAP GUI for Java throws a java.lang.NullPointerException. The operation will then be aborted.

Small disclaimer (thereby fulfilling SAP's guidelines for blogging): While I work at SAP, these opinions are my own. Especially the policy regarding unsupported operating systems.

SAP GUI for Java is SAP's GUI solution for customers that do not use Microsoft Windows or that do not want to use SAP GUI for Windows for some reason. Officially, it is only supported on the following platforms (I have excluded the various flavours of Windows and several other systems. For a full list, see the official SAP document):

• Mac OS X 10.4, 10.5
• SuSE 10.1, SuSE Linux Enterprise Desktop 10
• RedHat Enterprise Linux 4, 5
• Fedora 7, 8, 9
• Open SuSE 10.2, 10.3

What a shame: FreeBSD is not mentioned. The following steps will show you how to install and use SAP GUI for Java under FreeBSD. Why would you want to do that, anyway? One simple, convincing, and perfectly logical reason: Because we can.

The usual disclaimer: Until Tartarus freezes over, don't expect any support from SAP for that.

That being said, the program actually works. I have tested some transactions (see the screenshots later) and encountered no errors. YMMV.

Requirements: You need a working FreeBSD system (I did this with FreeBSD 7.1), the usual X11 ports and a SUN JRE from /usr/ports/java/linux-sun-jre16. I am also assuming that the Linux ABI support is available and works. If you need help with these steps, the appropriate handbook section might help. Grab SAP GUI for Java (choose the Linux version, for example PlatinGUI-Linux-710r7.jar).

Installation: cd to the directory where the installer is located. Use the JRE to start the installation process by executing the following command in a terminal (change the filename if necessary):

/usr/local/linux-sun-jre1.6.0/bin/java -jar PlatinGUI-Linux-710r7.jar 

Choose any installation directory and proceed with the install process. When it has finished, check your selected directory for the folder SAPClients.

After the installation: Open the file SAPClients/SAPGUI7.10rev7/bin/guilogon in a text editor of your choice. Change all references of /usr/bin/test to /bin/test. Finally, set the PLATIN_JAVA variable to your JRE. For example, with tcsh you would to the following:

setenv PLATIN_JAVA /usr/local/linux-sun-jre1.6.0/bin/java

That's it. You can now run SAP GUI for Java and work with your SAP system. If you don't have one, you might want to download a MiniSAP system for Linux or Windows. Trying to install this under FreeBSD is another story...

Finally, some nice screenshots with FreeBSD 7.1, XFCE, and SAP GUI for Java 7.10rev7:

• Fun with transaction SBWP.
• The "About" dialog. Note how the OS is declared to be Linux. Nice, is it not?
• XFCE's transparency effects also work.

Dokuwiki is a nice Wiki system if you don't need tons of extra features and plugins. If you happen to have a phpBB2 installation running, too, you can tell Dokuwiki to use this database to authenticate users. Here's how that works.

The following changes should be made to your local.php configuration file. The might get overwritten if you store them elsewhere. Here is an excerpt from my configuration file:

/* you want ACLs and MySQL */
$conf['useacl'] = 1; 
$conf['authtype'] = 'mysql'; 

/* I do not want users to register via Dokuwiki */
$conf['openregister']= 0; 

/* check the MD5-hash via MySQL */
$conf['auth']['mysql']['forwardClearPass'] = 1;

Moreover, you have to configure the database connection:

$conf['auth']['mysql']['server']   = 'your server';
$conf['auth']['mysql']['user']     = 'your username';
$conf['auth']['mysql']['password'] = 'your password';
$conf['auth']['mysql']['database'] = 'your database';

Pay special attention to the values of TablesToLock. If you use a specific table in a query, add this table to the array:

$conf['auth']['mysql']['TablesToLock']= array( "your_table", 
"your_table AS another_table" );

As a last step, we have to define some queries Dokuwiki uses for certain actions. The names are quite telling, so I will not explain them in great detail.

$conf['auth']['mysql']['checkPass']= "  SELECT user_password AS login
                                        FROM forum_users /* change it :-) */
                                        WHERE
					username='%{user}'
                                        AND
					user_password=MD5('%{pass}')";

$conf['auth']['mysql']['getUserInfo'] = "SELECT user_password AS pass, 
					 username AS name, user_email
					 AS mail
                                	 FROM forum_users
					 WHERE
					 username='%{user}'";

/* this query is from the dokuwiki documentation */
$conf['auth']['mysql']['getGroups']   = "SELECT a.group_name AS `group`
		                         FROM forum_groups a, 
					 forum_users b, 
					 forum_user_group c
	                                 WHERE b.user_id = c.user_id
                     			 AND
					 a.group_id = c.group_id
					 AND
					 b.username='%{user}'";

For all those black hats laughing right now because they see SQL injection possibilities: No way. The strings are escaped by the Dokuwiki authentication code. However, I would not use that method for any vital applications. Then again, if they are vital, you'd probably be writing your own wiki anyway...

A last remark: There are more options which you could add (searching for users via the user manager, updating user information etc.). This article show the absolute minimum you need to supply. To set the proper access rights, just add the groups you have in your phpBB2 installation to the acl.auth.php file. I would advise you to use the built-in group management system of phpBB2 because you will almost certainly need user groups in your discussion forum, too.

Let's start with something easy: A null modem cable is definitely not an RJ45 network cable. Furthermore, it won't work when plugged into a VGA connector.

Now it's becoming more advanced: If your IP address is 10.0.0.1 and the IP address of another device that is connected via a cross-over network cable to your computer is 192.168.0.1, you should change your IP address. No, it won't work if you use 192.168.0.1, too. And no, the device will not change its IP address on its own.

And a last one (at least for now): File names are very sensitive. They get angry if you do not use their real name. Keep in mind that these involves the case and the file extension. For example: ID10t is not equal to iD10T. The file extension is sometimes not shown by Windows. You might consider using a real operating system. However, true IT pros know an amazing trick: They are able to tell Windows to permanently show the file extension!

We all know that some people boast about their virtually non-existant skills. "Project Epsilon" tries to teach them at least a very small part of the subject involved. Hence, it is called epsilon, just like the mathematical epsilon that is used to describe small numbers.

Please keep in mind that the events described in "Project Epsilon" actually happened. Sad, but true.

You are able to participate: Either send me your own stories, which I will publish, or start your own "Project Epsilon". I am looking forward to hearing from you.

I am currently preparing a non-comprehensive guide about all administrative tasks I have to face at work. Unfortunately, this is necessary because I am the only full-time adminstrator at the moment. My colleague has quit some months ago which basically leaves me in charge.

However, a new administrator will soon arrive. To make life easier, I started the guide so that every new admin may have a look at what previous generations have done. Well, that sounds almost like Lord of the Rings...

So my day contains endless hours of typing LaTeX code. It's really nice and interesting, but sometimes, things are very obfuscated. For example, if you want to have sans-serif fonts, you have to issue the following line in the header:

\renewcommand{\familydefault}{\sfdefault}

Sooner or later, the guide will be finished and perhaps I am going to publish it via lulu.com. These guys seem to offer pretty interesting services.

Have fun. I am signing off after a long day of LaTeX...