Eclipse IDE debugging - code not reflects new changes

Question

I'm using Eclipse IDE (4.2). When I make a change in Eclipse and try to debug it, the previous version is compiled, but not the new one. To get around this, I do maven clean/build and then refresh the project. But this is very tedious and I need to do it every time I make any changes. Is there another way around this or a plugin that I can use to pick up these changes automatically?

Is `Project -> Build Automatically` ticked? And did you save the relevant file before debugging? — Absurd-Mind, Apr 30 '14 at 13:20
Hi, the project is saved. Im new to Eclipse, is there a tickbox to trigger the build automatically when i save it? Or do i need to go Project >> Build Automatically — user648244, Apr 30 '14 at 13:33
When you click Project in the title bar you should see a tick left of `Build Automatically`, if not click it one time. — Absurd-Mind, Apr 30 '14 at 13:35
that still does not work, seems like i still have to clean/install with maven .. — user648244, Apr 30 '14 at 14:00
That's odd. What Kind of Project is it? Are there any error (in `Problems` section)? Can you provide a screenshot of your eclipse? — Absurd-Mind, Apr 30 '14 at 14:04
Just a basic java application. It seems that eclipse packages the module as a jar and then during debug/compilation runs the code from jar. Is there a way to avoid this? or an automated process? similar to Intellj — user648244, Apr 30 '14 at 14:22
No, it doesn't. It builds all classes to `target/` directory and runs them from there. Is your project a dependency used by a different project? — Absurd-Mind, Apr 30 '14 at 14:28

score 5 · Accepted Answer · answered May 01 '14 at 04:31

5

Click Project > Build Automatically once and make sure that tick mark is appeared in front of Build Automatically option.

Also you have to enable hot code replace options. Click Windows > Preferences. Go to Java > Debug select all options in Hot Code Replace group

answered May 01 '14 at 04:31

Chandrayya G K

8,719
5
40
68

1

Its still Not working, I have tried the same operation in Eclipse Neon and Mars2 . Its picking the old complied jars from the target. Not not will automatically at all. Its annoying to clean and build jars again and again even making a small changes. Will look for more suggestion pls. – user216112 Apr 21 '17 at 06:28

score 2 · Answer 2 · answered May 24 '16 at 17:39

I had the same problem and these steps fixed it:

Run -> Run configurations
Select the one giving the problem
Go to the Source tab
Make sure your project is the first entry there
Mine had just the Default set there so I had to do this: Add -> Java Project -> Select your Project and add it

score 0 · Answer 3 · edited Jan 14 '22 at 18:36

I had the same problem, the reason was a wrong configuration of the javabuilder in the .project managed by Eclipse. I opened it and rewrote the buildspec section so that either Maven or jdt.core can compile. Once done, relaunch Eclipse and if the Project > Build Automatically option is enabled, any change should now be reflected:

<?xml version="1.0" encoding="UTF-8"?>
 <projectDescription>
  <name>ProjectName</name>
  <comment>My beautiful project</comment>
  <projects>
  </projects>
  <buildSpec>
    <buildCommand>
        <name>org.eclipse.jdt.core.javabuilder</name>
        <arguments>
        </arguments>
    </buildCommand>
    <buildCommand>
        <name>org.eclipse.m2e.core.maven2Builder</name>
        <arguments>
        </arguments>
    </buildCommand>
  </buildSpec>
  <natures>
    <nature>org.eclipse.m2e.core.maven2Nature</nature>
    <nature>org.eclipse.jdt.core.javanature</nature>
  </natures>
 </projectDescription>

Eclipse IDE debugging - code not reflects new changes

3 Answers3

Linked