Question: I find reading coding style guidelines to be the best way to get to know a language and its peculiarities. I've been trying to find a good document for Java, and get some questions answered immediately. 

Firstly, what is the convention for very long lines? Writing in both Java and C/C++ leads me to have a great deal of confusion on this point. 

Secondly, what is the guideline for creating custom exception classes? I typically end up throwing an existing exception rather than creating my own. Is custom exception creation typically enforced?

Answer: 
Take a look at the official [Code Conventions for the Java TM Programming Language](http://www.oracle.com/technetwork/java/codeconv-138413.html).
1. <http://www.oracle.com/technetwork/java/codeconv-138413.html>
2. Wrap to 80 - 110 chars
3. It is great to throw existing. You should only create custom, when
existing exception doesn't quite
match the exceptional case (
usually a business rule )

As a brief for the coding conventions:

```
class SomeClassName { //<-- Class with upper case, camel case
   public static final int CONSTANT_SOMETIHNG = 0x2A; // constants all upper case
   private int secretVariable; // variables start with lowercase
   public void someMethod() {  // methods too 

       // opening brace goes in the same line 

       if( cond ) { 
           ...
       } else { 
           ...
       }
       for( .. ) {
       }
       while( ... ) { 
       }
       try { 
       } catch() { 
       } finally {
       }
       // closing brace aligned to the element start 

    }
  }
}

```

Etc. etc.