The JVM interprets the bytecode just as a CPU would interpret assembly-language instructions.
At runtime, the JVM reads and interprets .class files and executes the program's instructions on the native hardware platform for which the JVM was written. The JVM is a piece of software written specifically for a particular platform. The JVM is the heart of the Java language's "write-once, run-anywhere" principle. Your code can run on any chipset for which a suitable JVM implementation is available. JVMs are available for major platforms like Linux™ and Windows®, and subsets of the Java language have been implemented in JVMs for mobile phones and hobbyist chips.