To compile:
gcj --classpath=.:lib:lib/iText-2.1.4_mod.jar:lib/bcprov_new1.4.jar -C src/Layers3PDF.java (or) javac -cp .:lib:lib/iText-2.1.4_mod.jar:lib/bcprov_new1.4.jar src/Layers3PDF.java
javac -cp .;lib;lib\iText-2.1.4_mod.jar;lib\bcprov_new1.4.jar src\Layers3PDF.java
cd src (or) cd lib (if using pre-compiled Layers3PDF.class)
then,
java -cp .:../lib:../lib/iText-2.1.4_mod.jar:../lib/bcprov_new1.4.jar Layers3PDF
Windows:
java -cp .;..\lib;..\lib\iText-2.1.4_mod.jar;..\lib\bcprov_new1.4.jar Layers3PDF