Why do we need a magic number in the beginning of the .class file?

Question

I read a few posts here about the magic number 0xCAFEBABE in the beginning of each java .class file and wanted to know why it

Answer 1

Magic numbers are a common technique to make things, such as files, identifiable.

The idea is that you just have to read the first few bytes of the file to know if this is most likely a Java class file or not. If the first bytes are not equal to the magic number, then you know for sure that it is not a valid Java class file.