Traditionally, a Java application cannot run without a JRE because the JRE provides the JVM and core libraries required for execution. However, modern Java versions allow developers to package a custom runtime with the application, eliminating the need for a separate JRE installation on the target machine.
Key Points: • A Java application requires a JVM and Java runtime libraries to execute.
• In older Java versions, these components were provided through a separately installed JRE.
• Starting with Java 9, the jlink tool can create a custom runtime image containing only the required Java modules.
• This custom runtime can be bundled with the application, allowing it to run without a standalone JRE installation.
• Bundling a custom runtime reduces application size and simplifies deployment.
Example: A desktop Java application can be packaged with a custom runtime created using jlink. Users can run the application directly without installing Java or a JRE on their systems.
Interview Tip: A concise interview answer is:
"Normally, a Java application requires a JRE because it contains the JVM and necessary libraries. However, from Java 9 onward, tools like jlink allow developers to package a custom runtime with the application, so a separate JRE installation is no longer required."