Allow stepping through disassembly

[danthe1st]

What it does

This PR allows stepping through the bytecode of disassembled classes in the class file editor.

This is just an unfinished prototype but I wanted to create a (draft) PR early to be able to get feedback and show the basic approach.

This depends on another PR in jdt.ui (eclipse-jdt/eclipse.jdt.ui#2708)

@SougandhS Since you have worked on similar things recently, I think you might be interested in that.

TODO

• ensure the relevant instruction is unselected/the highlighting is removed when no longer stepping through that class
• Ensure that editors aren't duplicated (?)

How to test

• Start Eclipse with this change as well as this patch
• Step through some code that steps into libraries without a source attachment
• It automatically jumps to the relevant bytecode instruction(s) corresponding to the stack frame
• Stepping through normal (non-library) classes and library classes with source attachments should still work

Author checklist

• I have thoroughly tested my changes
• The change is following the coding conventions
• I have signed the Eclipse Contributor Agreement (ECA)

[SougandhS]

Thanks for the feature @danthe1st, looks great on feature wise

Would it be possible to change highlight color for dark theme ? its bit hard to read

[eclipse-jdt-bot]

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

org.eclipse.jdt.debug/META-INF/MANIFEST.MF

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From 0fc0c7499e1927da534bae46cee3001370717b67 Mon Sep 17 00:00:00 2001
From: Eclipse JDT Bot <jdt-bot@eclipse.org>
Date: Thu, 1 Jan 2026 05:20:08 +0000
Subject: [PATCH] Version bump(s) for 4.39 stream


diff --git a/org.eclipse.jdt.debug/META-INF/MANIFEST.MF b/org.eclipse.jdt.debug/META-INF/MANIFEST.MF
index 9afbed70f..bef1c1bbb 100644
--- a/org.eclipse.jdt.debug/META-INF/MANIFEST.MF
+++ b/org.eclipse.jdt.debug/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.jdt.debug; singleton:=true
-Bundle-Version: 3.25.0.qualifier
+Bundle-Version: 3.25.100.qualifier
 Bundle-ClassPath: jdimodel.jar
 Bundle-Activator: org.eclipse.jdt.internal.debug.core.JDIDebugPlugin
 Bundle-Vendor: %providerName
-- 
2.52.0

Further information are available in Common Build Issues - Missing version increments.

[danthe1st]

@SougandhS I updated this to use the current instruction pointer background color (see the updated screenshots).

Do you know whether there is a way to detect when the stack current stack frame is no longer there/when the highlighting should be removed (e.g. when resuming or stepping into a different file)?

[SougandhS]

@SougandhS I updated this to use the current instruction pointer background color (see the updated screenshots).

Thanks, much better now

Do you know whether there is a way to detect when the stack current stack frame is no longer there/when the highlighting should be removed (e.g. when resuming or stepping into a different file)?

You can achieve this by registering an IDebugContextListener and check that stackframe's status accordingly

[danthe1st]

@SougandhS Hi. Now that I was able to write a test for this as well, I think eclipse-jdt/eclipse.jdt.ui#2708 and this are ready for review.

Note that this won't be able to build successfully without eclipse-jdt/eclipse.jdt.ui#2708.
Also, as you probably see, I am not that experienced with the tests here ;).