What ??? - "com.thoughtworks.selenium.SeleniumException: syntax error"

At times during development of Selenium tests you come across errors which don't give you any clue what so ever. One such error is -

com.thoughtworks.selenium.SeleniumException: syntax error
or -

missing ) after argument list

One such occurnce of this error is when you use waitForCondition method.

This is one awesome selenium method which saved you from using ugly sleep statements in your scripts. Having read it's API you might consider using it as -

waitForCondition("selenium.isElementPresent(//a[text()='Dashboard'])", "60000");

where first argument - selenium.isElementPresent(//a[text()='Dashboard']), is the condition you expect to be true. And second argument - 60000, is the max wait period till selenium would wait for condition to be true (You don't hard code time in your scripts, do you?).

Looks simple, is not it? Execute (well, after changing locator - //a[text()='Dashboard'] to match your application) it and you end up with -

com.thoughtworks.selenium.SeleniumException: syntax error

Let's try to understand it. Thing, which you should instantly doubt on is the argument - 

selenium.isElementPresent(//a[text()='Dashboard'])

Do you usually use it this way? No you do not. isElementPresent is itself a method which takes String argument. So you use it as -

selenium.isElementPresent("//a[text()='Dashboard']")

But then this entire statement is itself first argument for waitForCondition method. So if you try to write -

waitForCondition("selenium.isElementPresent("//a[text()='Dashboard']")", "60000");

in java editor (Eclipse, IntelliJ etc), you would see compilation errors, because in argument -

"selenium.isElementPresent("//a[text()='Dashboard']")"

you used quotation twice. once with "selenium.isElem.... and then with "//a[text()='Dashboar....

And now you realize that you need to escape the second instance of quotation in your argument as

"selenium.isElementPresent(\"//a[text()='Dashboard']\")"

Whole method would look as -

waitForCondition("selenium.isElementPresent(\"//a[text()='Dashboard']\")", "60000");

And you test executes with out any error.

But then you don't hard code locators in the you test, which is - //a[text()='Dashboard'] in our case.

Consider that you are storing them in a class as static methods, returning String locators. 
In the following example there is third set of quotation introduced in first argument of waitForCondition method to concatenate UserDashboard.getDashboardLocator() with rest of the string.