Eclipse: editing and running code in real time

Question

When editing Java code in Eclipse, I can modify the code while it works in different ways and make changes to them without reloading my program.

What is the technology behind this feature? Is this part of Eclipse, or is this what I can do with command line tools and tools supplied with the JDK?

Answer 1

Its part is JVM and its called HotSwap.

http://download.oracle.com/javase/1.4.2/docs/guide/jpda/enhancements.html

Answer 2

This function is usually called "hot code replace" and was introduced in Java 1.4 - this is part of the debugging interface of the Java virtual machine and various APIs in addition to this.

So this does not apply to Eclipse, but I do not think that any of the command line tools that come with the JDK supports it.