Java bytecode is a compiled code of a Java program or we can say it is a set of instructions for JVM. It can execute on any platform which has a Java installation. After compilation, the Java code is converted into .class file which is also known as bytecode.
Java is machine independent because of the JVM(Java virtual machine) that runs the bytecode in the processor. Also Java programmer doesn’t require knowledge about the specific OS and processors where the program will run because JVM takes care of those.