An important thing to remember, when posting a question to Java Ranch (or any other forum), is that the people who will help you are not getting paid to do so. They're going to take time from their own work (or from leisure activities) to help solve your problem, for free.
While it's nice to SayThanks, the best way to show your gratitude for their effort is to be respectful. What does that mean? Take some time and try and find the answer yourself first. Google is a great tool. The ranch has it's own built in search feature that lets you focus your search to specific forums. Often such a search will give you results faster than waiting for someone to reply. If you do search and don't understand what you find, post what you found, and explain why it doesn't make sense, or why you think it's wrong. Making an effort shows folks you care about learning, and not just the answer. Further, an important skill of any developer is to learn how to research problems, and this is a good start down that path.
Give as much detail as you can. If there is an error message, post the ENTIRE error message. Paraphrasing doesn't help much, especially since those messages give you details on the line and even the exact spot where the compiler thinks the error is.
Cross posting and not reading the FAQ section before asking a question that's been asked numerous times are some examples of being disrespectful. Please, CarefullyChooseOneForum and SearchFirst before posting your question.
Be precise in how you post things.
For example, saying:
'My class files are under /myapp/web-inf/classes'
instead of saying:
'My class files are under /myapp/WEB-INF/classes'
This will waste the time of someone trying to help you. That person will assume that you've accidentally created the 'web-inf' directory with lower case letters (a bug in J2EE app servers). They will spend their time pointing this out to you only to find out later that the directory name really was 'WEB-INF' but you didn't hold down the caps lock button when typing your question. If you're lucky, that person might continue to look at your problem to see what else might be wrong. More likely, that person will just move on.
There is a phrase in the English language called "A Red Herring" (see link below) used by lawyers to describe the practice, of distracting police from real evidence that could help them solve a crime by planting false evidence. Take the utmost care not to drag a red herring (see the last example) across the path of someone trying to help you. (See: AvoidRedHerrings) Doing so will almost certainly cause them to walk away from your thread in frustration. This can be tricky for beginners, since you may genuinely think you are providing an important tip, so at least consider carefully what you post.
Cut'N'Paste is your friend
'I've added all the necessary properties to the config file.'
It would be just as easy, and a lot more useful, to cut and paste the relevant parts of the config file into the message. This would allow the person helping you to verify that you have, indeed, added the necessary properties without needing to take the time to ask you and wait for you to post the contents of your config file.
By far, the most common way to show disrespect is to skimp on punctuation or to not UseRealWords. It's much more difficult to determine the nature of someone's problem if you have to burn your brain's CPU cycles translating contractions like 'ur' instead of 'you are' or 'plz' instead of 'please'. It's also very draining to read a block of text if there is no punctuation at the end of each sentence, especially if there is no capitalization at the start of the next sentence.
Put as much effort into presenting your question as you would hope someone will put into answering it.
Do not presume that other people's time is so much less valuable than yours that you can afford to take shortcuts when typing your question - especially if doing so causes them to have to expend more effort just to figure out what you're asking.