Easy way to concatenate two byte arrays

Question

What is the easy way to concatenate two byte arrays?

Say,

byte a[];
byte b[];

How do I concatenate two byte

Answer 1

Merge two PDF byte arrays

If you are merging two byte arrays which contain PDF, this logic will not work. We need to use a third-party tool like PDFbox from Apache:

ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
mergePdf.addSource(new ByteArrayInputStream(a));
mergePdf.addSource(new ByteArrayInputStream(b));
mergePdf.setDestinationStream(byteArrayOutputStream);
mergePdf.mergeDocuments();
c = byteArrayOutputStream.toByteArray();