Answer 1

Bytecode is the program code that compiled for a virtual machine instead for the particular computer hardware architecture like in the case of my C/C++.

Java is one of the popular language that uses bytecode for it's virtual machines (JVM) in order to make your program compatible over cross platforms. Search the open Internet for more detail.

So to see the bytecode, for example in the case of Java when you compile your program it is converted into bytecode and placed in the .class file. Many of the IDEs now a days are able to view the .class files and the alternative online tools are also available that views the code online on uploading .class file(s).