this utility is able to merge PDF files into a single one
1- open a terminal and run the following command: mvn clean compile assembly:single
2- then you can procede to run the command: mvn package
3- after the maven process will be finished you should the following jar inside target directory: mergePDF-1.0-SNAPSHOT-jar-with-dependencies.jar
1- Copy the jar file inside the current directory where there are the pdf file you want to merge
2- Open a terminal in the current directory
3- run the following command: java -jar mergePDF-1.0-SNAPSHOT-jar-with-dependencies.jar file1.pdf file2.pdf file3.pdf
N.B. file1.pdf, file2.pdf, file3.pdf are the filename you want to merge; you can list as many files as you want.