Are Pascal and Object Pascal (Delphi) two different languages?
Well... Pascal is ancient and defined by Wirth in the 60s. Since then, Borland added some object-oriented features to the language back in its ver 5.5 of Turbo Pascal.
After that, a more professional approach towards Pascal's OOP was taken, so Object Pascal appeared, with all the nice features like optimised handling of strings, class interfaces, RTTI, and some metaclass stuff. Object Pascal was defined by...Apple (surprise, eh?) and implemented by many, including Borland in its Delphi.
After purchase of Borland by Embarcadero, further stuff was added to the language, like templates (generics) in Delphi 2010 (or 2009?). Now it's a fairly modern language as far as compilable languages could go.
As of transiting from Java to Pascal, imagine that you dont have classloading and garbage collector, pretty everything else is in place and has an equivalent (although the syntax is different). I would strongly recommend you to make heavy use of the try..finally construct right away in your projects, so you free the allocated resources (objects and system handles, closing files etc) guaranteed, even if an exception occurs.
In case of an exception, it executes the finally sections, then goes further up the call stack to handle the exception, exactly as in Java. Except that Java made programmers so lazy that they dont close files in finally sections, leaving it at the mercy of gc, so it's pretty common to see a Java program to hold a file open until you explicitly quit the program. :)