Allow highlighting instructions in ClassFileEditor

[danthe1st]

What it does

This PR allows selecting/highlighting instructions in the class file editor using:

• method name
• method signature
• code index (position in the method which is displayed at the beginning of a class file)

This is used to view the current instruction pointer when debugging class files without attached sources (the debugging part is implemented in eclipse-jdt/eclipse.jdt.debug#831.

video:

Screencast_20260402_144851.webm

Ideally, this would be done without needing to "parse"/search through the disassembly text but I don't think there is a good way to do that

How to test

See eclipse-jdt/eclipse.jdt.debug#831

Author checklist

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

[iloveeclipse]

Screenshot?

[danthe1st]

Screenshot?

I plan to add one but I currently have issues with my development setup after rebasing it.

[danthe1st]

Screenshot?

Added.

[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.ui/META-INF/MANIFEST.MF
org.eclipse.jdt.ui/pom.xml

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 7fdb94e31eb87cf1ef0f8b90aca655993cbaa494 Mon Sep 17 00:00:00 2001
From: Eclipse JDT Bot <jdt-bot@eclipse.org>
Date: Sat, 28 Feb 2026 13:11:39 +0000
Subject: [PATCH] Version bump(s) for 4.40 stream


diff --git a/org.eclipse.jdt.ui/META-INF/MANIFEST.MF b/org.eclipse.jdt.ui/META-INF/MANIFEST.MF
index 2d6f4e8ff1..2b3c023d46 100644
--- a/org.eclipse.jdt.ui/META-INF/MANIFEST.MF
+++ b/org.eclipse.jdt.ui/META-INF/MANIFEST.MF
@@ -3,7 +3,7 @@ Automatic-Module-Name: org.eclipse.jdt.ui
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.jdt.ui; singleton:=true
-Bundle-Version: 3.37.0.qualifier
+Bundle-Version: 3.37.100.qualifier
 Bundle-Activator: org.eclipse.jdt.internal.ui.JavaPlugin
 Bundle-ActivationPolicy: lazy
 Bundle-Vendor: %providerName
diff --git a/org.eclipse.jdt.ui/pom.xml b/org.eclipse.jdt.ui/pom.xml
index 59b583dcf7..2ac6bd499d 100644
--- a/org.eclipse.jdt.ui/pom.xml
+++ b/org.eclipse.jdt.ui/pom.xml
@@ -18,7 +18,7 @@
   </parent>
   <groupId>org.eclipse.jdt</groupId>
   <artifactId>org.eclipse.jdt.ui</artifactId>
-  <version>3.37.0-SNAPSHOT</version>
+  <version>3.37.100-SNAPSHOT</version>
   <packaging>eclipse-plugin</packaging>
 
 	<build>
-- 
2.53.0

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

[danthe1st]

(push is just rebasing)

@iloveeclipse Would you like to review this?

[danthe1st]

Alternatively, would you be interested in reviewing this/share your thoughts? @jjohnstn
If you have a better idea than parsing the class file output (that wouldn't make the PR much more complicated), I'll happily take a look at that as well.

[danthe1st]

Sorry to ping random committers but I didn't get a review until now and I think something along the lines of this could be useful for anyone wanting to view what is going on in some library where the source could not be resolved.

@trancexpress

[trancexpress]

I'll try to take a look on Sunday, I hope that isn't too late?

[trancexpress]

Just two small things from me, I'll let Copilot also do a review here.

[Copilot]

Pull request overview

This PR adds support in the JDT ClassFileEditor (no-source/disassembly view) to programmatically highlight a specific bytecode instruction by method + signature + code index, enabling external tooling (e.g., debugging) to show the current instruction pointer when source isn’t available.

Changes:

• Added instruction highlighting/unhighlighting API to ClassFileEditor, including lightweight parsing/caching of disassembly text to locate instructions.
• Introduced a new internal preference key constant intended to source the instruction-pointer highlight color.
• Added JUnit tests for highlighting behavior and wired them into the automated test suite.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ClassFileEditor.java	Adds highlight/unhighlight logic, disassembly parsing + caching, and preference-based color initialization.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/IUIConstants.java	Adds a constant for the instruction-pointer color preference key.
org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/editor/ClassFileEditorTests.java	New tests validating instruction highlighting behavior in the disassembly widget.
org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/AutomatedSuite.java	Includes the new test class in the automated suite.

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