View source for FAQ What is hot code replace?

Hot code replace (HCR) is a debugging technique whereby the Eclipse debugger transmits
new class files over the debugging channel to another VM. In the case of
Eclipse development, this also applies to the VM that runs the runtime 
workbench. The idea is that you can start a debugging session on a 
given runtime workbench and change a Java file in your development 
workbench, and the debugger will replace the code in the receiving 
VM while it is running. No restart is required, hence the reference to &#147;hot.&#148;

HCR has been specifically added as a standard technique to Java 
to facilitate experimental development and to foster iterative trial-and-error coding.
HCR only works when the class signature does not change; 
you cannot remove or add fields to existing classes, for instance.
However, HCR can be used to change the body of a method.
HCR is reliably implemented only on 1.4.1 VMs and later, or using
any version of the IBM J9 VM. J9 is available in IBM products such as 
Websphere Studio Device Developer&#153;.


== See Also: ==


The WSDD Web site (http://ibm.com/software/wireless/wsdd/)

<hr><font size=-2>This FAQ was originally published in [http://www.eclipsefaq.org Official Eclipse 3.0 FAQs]. Copyright 2004, Pearson Education, Inc. All rights reserved. This text is made available here under the terms of the [http://www.eclipse.org/legal/epl-v10.html Eclipse Public License v1.0].</font>