String, text, numbers, I/O I part

Answer:

int in; ...

byte b1 = (byte)(in & 0xff);

byte b2 = (byte)((in >> 8) & 0xff);

byte b3 = (byte)((in >> 16) & 0xff);

byte b4 = (byte)(in >>> 24);

: How do I restore the original value of the long (or int) variable back

: from the bytes that i have just created then?

Answer:

int in = (b1 & 0xff) | ((b2 << 8) & 0xff00) |

((b3 << 24) >>> 8) | (b4 << 24);

by Tim Tyler

 Is there any Java API allowing creating easily PDF files (Adobe Acrobat type)

including images?

Answer: No, just text

Etymon  PJ is a developer toolkit for parsing, modifying, and creating PDF

documents. 

http://www.etymon.com/pj/index.html

Are there any public domain matrix/linear algebra java packages out there?

I m mainly interested in solving systems of equations and finding matrix inverses.

Answer: http://math.nist.gov/javanumerics/

The JavaNumerics page provides a focal point for information on numerical

computing in Java.

Does anyone know how to write multi line string in Java?

Answer: Something like this:

String a =

     "This is a

            multiline string.";

It is really pain to print HTML or XML from the Java program. Perl offer something

like this:

print <