Difference Between JRE and JDK
The difference between JRE (Java Runtime Environment) and JDK (Java Development Kit) lies in their purpose and components.
1. JRE (Java Runtime Environment)
- Purpose: Used to run Java applications (not to compile Java applications).
- Components:
- JVM (Java Virtual Machine): Executes Java bytecode.
- Core Libraries: Provides essential libraries required for Java programs to run.
- Runtime Environment: Manages application execution.
- Who Needs It? If you only need to run Java applications and not develop them, JRE is sufficient.
2. JDK (Java Development Kit)
- Purpose: Used to develop and run Java applications.
- Components:
- JRE (which includes JVM, core libraries, and runtime environment).
- Development Tools: Compiler (
javac), debugger (jdb), JavaDoc (javadoc), and other utilities.
- Who Needs It? If you are a developer writing Java code, you need JDK to compile and build Java applications.
3. Conclusion
- If you only need to run Java programs → Install JRE.
- If you need to develop Java programs → Install JDK (which already includes JRE).
| Feature | JRE | JDK |
|---|---|---|
| Contains JVM? | ✅ Yes | ✅ Yes |
| Contains JRE? | ✅ Yes | ✅ Yes |
Includes Compiler (javac)? |
❌ No | ✅ Yes |
| Includes Development Tools? | ❌ No | ✅ Yes |
| Purpose | Run Java applications | Develop and run Java applications |