Java Architecture

What is Java Architecture?
Java architecture explains how a Java program runs — starting from source code to the final output.
It mainly involves three components: JDK (Java Development Kit), JRE (Java Runtime Environment), and JVM (Java Virtual Machine).
When we write Java code, the compiler converts it into bytecode, which is platform independent.
This bytecode is then executed by the JVM, which converts it into machine code for the specific operating system.
This is what makes Java platform-independent and portable.

What is JDK?
The Java Development Kit (JDK) is the complete software package used by developers to create, compile, and run Java programs. It includes all necessary tools such as the compiler (javac), debugger, and other utilities, along with the Java Runtime Environment (JRE).

What is JRE?
The Java Runtime Environment (JRE) provides the environment required to run Java applications. It contains the Java Virtual Machine (JVM), core class libraries, and other files that support program execution. In other words, the JRE does not help in developing programs but only in running them.

what is JVM?
The Java Virtual Machine (JVM) is the core part of Java architecture responsible for executing Java bytecode. It converts platform-independent bytecode into machine-specific code so the program can run on any operating system. The JVM also manages memory allocation, garbage collection, and provides security and exception handling. Together, the JDK, JRE, and JVM form the foundation of Java’s “write once, run anywhere” capability, making Java a truly platform-independent programming language.

• JDK → Platform dependent (used for development).
• JRE → Platform independent (used for running programs).
• JVM → Platform independent at the bytecode level (executes Java code across all systems).