Java

Java Virtual Machine(JVM)

Java Virtual Machine (JVM) is a implementation of a machine that executes programs like a physical machine.

WORA (Write Once Run Anywhere), JVM runs on all kinds of hardware to execute the Java Bytecode without changing the Java execution code.

Features of JVM are :

1.  By primitive data type : " java virtual machine (JVM) defines the primitive data type to  maintain its  compatibility  and  guarantee platform independence".
2.  based on stack machine :most popular computer architectures such as Intel( x86)  Architecture and ARM  Architecture run based on a register. However, JVM runs  based on a stack.
3.  Order network byte:   Java class file uses network byte order to maintain platform  independence between  the little endian used by Intel( x86 Architecture) and the big  endian used by the RISC Series Architecture  " a fixed byte order must be kept.  Therefore, JVM uses the network byte order". (which is used for  network transfer).
4.  Symbolic : All types (class and interface) except for primitive data types are referred to  through  symbolic  reference- instead of through explicit (memory) address based  reference.
5.  Garbage collection(gc): A class instance is explicitly created by the "user code" and  automatically  destroyed  by "garbage collection".