1. 2.1. Compilers and Interpreters

2. Compile-Link Process
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3. Compilers and Interpreters

4. Compilers vs Interpreters

5. High-level View of a Compiler

6. Compilation

7. Interpretation

8. Language Implementation

9. Cross Compilation

10. Calling conventions

11. Static & Dynamic Allocation

12. Parameter Passing Mechanism

13. Call by Value

14. Call by Value Result

15. Call by Reference

16. Java Programming Environment
Java compiler produces an intermediate code known as byte code for a machine, known as JVM.
It exists only inside the computer memory.
Machine code is generated by the java interpreter by acting as an intermediary between the virtual machine and real machine.
Java Program
Java Compiler
Virtual Machine
Bytecode
Java Interpreter
Machine Code 16

17. Java Programming Environment
Compile-time environment
Run-time environment
A.java
B.java
C.java
Java compiler
A.class
B.class
C.class
Your program’s source files
Your program’s class files
Your program’s class files
A.class
B.class
C.class
Your class files move locally or through a network
Java
Virtual
Machine
Java
Interpreter
Object.class
String.class
Java API’s class files

18. What is ‘Java Virtual Machine’ …?
The abstract specification
A concrete implementation
A run-time instance
ByteCode (class files)
JVM
Linux
Win
Mac
Compiled Java Program
Java Virtual Machine
H/W Platform & OS

19. Java Virtual Machine Architecture
A.java
A.class
Java
Compiler
Compile source code
Java Virtual Machine
Loader
Network
B.class
Verifier
Linker
Bytecode Interpreter

20. Basic Block Diagram of JVM
Java Virtual Machine
Your program’s class files
Java API’s class files
Class Loader
ByteCodes
Execution Engine
Native method invocation
Host Operating System
RealTimeSystems Lab

21. Md. Samsuzzaman ,Lecturer Faculty of CSE, PSTU
Primary
Memory .
Disk
Editor
Compiler
Class Loader
Program is created in an editor and stored on disk in a file ending with .java.
Compiler creates bytecodes and stores them on disk in a file ending with .class.
Class loader reads .class files containing bytecodes from disk and puts those bytecodes in memory.
Phase 1
Phase 2
Phase 3
Bytecode Verifier
Bytecode verifier confirms that all bytecodes are valid and do not violate Java’s security restrictions.
Phase 4
Interpreter
Interpreter reads bytecodes and translates them into a language that the computer can understand, possibly storing data values as the program executes.
Phase 5
JVM
Md. Samsuzzaman ,Lecturer Faculty of CSE, PSTU
05/07/ Mosarratj Jahan, Dept. of CSE, DU 21

22. .NET Compilation and Execution
Also called Assembly
(.EXE or
.DLL file)
Source Code
Language Compiler
Code
MSIL
Metadata
Before installation or the first time each method is called
Execution
Native
Code
JIT Compiler

23. The Common Language Runtime Compilation and Execution
Source code written in Visual C#, Visual Basic .NET or another language that targets the CLR is first transformed into MSIL by the appropriate language compiler.
Before execution, this MSIL is compiled by the Just-in-Time (JIT) complier into native code for the processor on which the code will operate.

24. The Common Language Runtime Compilation and Execution
The default is to JIT compile each method when it is first called, but it is also possible to “preJIT” MSIL code to native code at assembly install-time.
With this option, all methods are compiled before the application is loaded so as to avoid the overhead of JIT compilation on each initial method call.

25. The Common Language Runtime Compilation and Execution
You use the Native Image Generator (Ngen.exe) to create a native image from a managed assembly and install it into the native image cache.
Once the code is compiled and cached, the CLR does not need to re-compile the MSIL code until the assembly is updated, the Just-In-Time compiled code is removed from the cache, or the machine is restarted.

26. summary

27. Interpreters

28. Compiler vs. Interpreter

29. Compiler vs. Interpreter