Pipeline
Big picture:
Inside:
Bytecode Interpreter
- JVM is a stack based abstract machine: bytecodes pop and push values on the stack
- local variables and parameters are stored in registers
Memory Allocators
Object allocation in Java invokes the JVM memory allocator. The JVM memory allocator often has to ask the underlying OS for memory which it then manages internally.
- JVM memory allocator works concurrently
Garbage Collectors
- works concurrently
- periodically free memory that are unreachable
- Concurrent garbage collectors are very difficult to get correct
Native Interface
When calling native methods, one convert the JVM parameters into machine registers following the calling convention
- some support concurrency some not
public static native int print(double d);