Question: I'm a Java newbie, but I am an experienced programmer (Assembler, COBOL, C/C++, REXX) 

I can't understand why the compiler is giving me the following:

```
[loading java\lang\Throwable.class(java\lang:Throwable.class)]
src\LU62XnsCvr.java:265: incompatible types
found   : java.lang.String
required: java.lang.StringBuffer

```

Code:

```
message_data = "LU62XCE0513: Request File I/O Exception =" ;

```

I've defined `message_data` as:

```
static StringBuffer message_data = new StringBuffer();

```

So why can't I place a simple literal `String` into the `StringBuffer` labeled `message_data` ? 
I mean BOTH are of type `String` .. right ??

Answer: 
No, `String` and `StringBuffer` are totally unrelated. Try

```
message_data.append("LU62XCE0513: Request File I/O Exception =");

```

While we're at it: note that `StringBuffer` is a legacy class, best replaced with `StringBuilder` in new code, except in the unlikely case that you need to share the object across threads. It's source compatible, so just change the name and you're fine.
Just call `message_data.toString()` when passing the message to the `Throwable`