Difference Between JVM And JIT, PDF

Java Virtual Machine is an interpreter that converts the bytecode into the machine’s native language, whereas JIT (Just In Time) is responsible for improving the environment of Java. Here, we will learn about these topics in detail.

Table of Contents

What Is JVM?

The JVM stands for Java Virtual Machine. The Java Virtual Machine provides portability for Java programming. It is platform-dependent and is responsible for executing the bytecode. JVM is in charge of various operations, like loading code, verifying code, and then executing it in a runtime environment. Its layered structure enables it to run bytecode on various operating systems. It also provides services such as management and security. Here are a few of the critical elements of the JVM architecture:

Class Loader
JVM Memory
Execution Engine
Native method interface
Native method libraries

JVM is in charge of transforming.java files into.class files. It provides computers with executable code that they can process.

Important Features of Java Virtual Machine

Java Virtual Machine has various applications and use cases. Here in this article, we will learn about some of the important features of JVM.

Platform-Independent: The most important part of having a Java environment in your system is that you only need to write the code once, and you can execute it anywhere. The JVM makes the Java platform independent.
Memory Management: JVM automatically manages the memory allocation and deallocation. It helps to prevent any type of memory leaks in the program and makes it more secure.
Security: It contains many security features, such as bytecode verification, which helps keep harmful malicious code away.
Exception Handling: It automatically handles the errors and handles them precisely. It helps developers write code without worrying about the exception-handling part.
Multi-threading: With the help of JVM, multiple threads can be executed simultaneously. It makes the system fast and responsive.
Class Loading: JVM loads the class dynamically when needed. It helps improve memory efficiency and performance.
Runtime Environment: It provides a runtime environment for the Java applications. It includes various libraries support and services.
Multiple Langauge Support: While Java is the primary language for the JVM but it also supports other programming languages like Kotlin, Groovy, Scala, etc.
Portability: JVM bytecode is a standardized format, which means that Java applications can run on any JVM-compatible platform without modification.
Debugging: JVM provides debugging tools and diagnostics options to help developers identify and fix any issues in their code.

What Is Just In Time (JIT)?

Just In Time is a compiler program that is present inside the Java Virtual Machine. It helps to improve the performance of Java by converting the bytecode into native machine code during runtime, just before the execution of the code.

The bytecode generated during the first compilation process is platform-independent. It is not possible to execute them directly. JIT helps to generate the native machine code for the specific hardware on which the program is running. At the end, the CPU processes the information generated by the JIT compiler. It helps make the program run faster and with fewer bugs.

Important Features of JIT

JIT stands for Just In Time compiler. It enhances the performance of the Java programs. It converts the bytecode into machine-native code just before executing the code. Some of the important features of JIT are mentioned here.

Dynamic Compilation: It compiles the code at runtime when the program is executing. It allows the compiler to make necessary optimizations during the actual execution of the program.
Improved Execution Speed: It converts the bytecode into native machine code for the specific operating system on which the program is running. It makes the native code execution faster than the bytecode, which helps to improve the performance.
Adaptive Optimization: Compilers with JIT can adapt according to the behavior of the program during runtime. They can help in optimizing the code and help in improving the performance.
Debugging Support: JIT compilers often provide options to generate debug-friendly code or to support debugging tools, making it easier for developers to debug optimized code.

Difference Between JVM And JIT

JVM and JIT are the two main components of the Java programming language. They are making a major contribution to making the code platform-independent. Let us now check some major difference between JVM and JIT, from the given table.

Difference Between JVM and JIT
Feature	JVM	JIT Compiler
Purpose	It executes the Java bytecode at runtime.	It compiles bytecode into native machine code at runtime.
Role	It is a runtime environment for Java applications.	It is a component inside the JVM that is responsible for compilation.
Compilation Time:	It does bytecode interpretation of bytecode before compilation.	The compilation of bytecode happens just before execution.
Platform Independence	It provides a platform-independent environment by running bytecode on any platform with a compatible JVM.	It generates a platform-specific native code that is optimized for the system on which the operating system is currently working.
Execution Performance	It is generally slower due to the interpretation of bytecode.	It is typically faster as it produces optimized native machine code.
Memory Management	It can manage memory, including garbage collection.	It generally focuses on code compilation and optimization, not memory management.
Security Features	It includes bytecode verification and other essential security measures.	It contributes to security indirectly by producing safe native code.
Dynamic Class Loading	It supports dynamic class loading and unloading.	It does not support dynamic class loading and is handled by the JVM.
Multithreading Support	Multithreading support is provided in the Java applications.	Although not directly connected, multithreading has advantages when running threaded applications.
Programming Languages	Primarily used for executing Java bytecode.	It is used in various languages (like JavaScript in V8 and .NET languages) as a compilation strategy.
Code Execution Control	It is also responsible for executing bytecode.	It is responsible for code compilation but doesn’t execute code directly.

Difference Between JVM and JIT FAQs

What is the full form of JVM?

The full form of JVM is Java Virtual Machine.

What is the full form of JIT?

The full form of JIT is the Just In Time Compiler.

Are JVM and JIT the same terms?

JVM executes the Java bytecode at runtime, and the JIT compiles the bytecode into native machine code at runtime. However, we discussed the major differences between them in detail.

Explain JIT and give an example.

The Just-In-Time (JIT) compiler is a runtime environment component that improves the performance of Java applications by compiling bytecodes to native machine code at runtime.