JAVA INTERNALS: JDK, JRE, JVM, and JIT!

Hello Everyone! Before learning Java, it is essential to understand how the Java process is carried out. I will explain them in simple language based on my understanding while learning Java.

What is JDK (JAVA Development Kit)?

• It will help us to write and develop Java programs.




• Whenever you write a program and try to compile it. This contains Java Compiler (javac), which checks for any syntax errors, and provides you with the error message along with the line number.




• If the program doesn't have any errors, then it converts the .java file to a .class file. This way, you understand our program doesn't have any errors.

What is JRE (Java Runtime Environment)?

• It is required to run Java applications. It takes the compiled .class file, and it helps to execute the program in the system.




• It provides core libraries that are required while the program is running.

WHAT IS JVM (JAVA VIRTUAL MACHINE)

-This plays a major role in the process, where it converts the bytecode into machine code.

• Manages memory (Heap & Stack)




• Execute the program, and this is why Java is a platform-independent, meaning write once, run anywhere(WORA)

JIT(JUST IN TIME COMPILER)?

• It is the JVM's Execution Engine. Converts byte code into machine code at run time.




• Improves performance and makes Java programs run faster




• Interpreter runs code line by line, but JIT compiles frequently used code for speed

JDK

JRE

JVM

JIT

Understanding the differences between these helped me clearly see how Java programs are developed and executed. As a beginner, learning these basics gives me confidence to move forward with core Java concepts.

More posts coming soon!!!