Errors "Unable to install breakpoint" when debugging code that uses Mockito.

[om-11-2024]

Let's make sure issue is not already fixed in latest builds first.

• [✓] I verified I can reproduce this issue against latest Integration Build of Eclipse SDK

Steps to reproduce

From a fresh installation and clean workspace:

1. Extract myapp.zip to local folder.
2. Import the folder as existing maven project in Eclipse
3. Set breakpoints in MyTest.java: for example on lines 16,18,20,21
4. Run MyTest.java as unit-test in debug mode => the execution will pause at the breakpoint on line 16
5. Press "Step Over" (or F6) to make a step in the code => Error dialogs appear

The dialog appears once per each breakpoint.

The error text:

Unable to install breakpoint in com.example.MyTest$TestExedcutorService$MockitoMock$NuTULI41 due to missing line number attributes. Modify compiler options to generate line number attributes.

Reason:
Absent Line Number Information

"Add line number attributes to generated class files" is set in the project settings.

Here is some relevant log output

There is nothing relevant in <workspace>/.metadata/.log

Tested under this environment:

• OS & version: Windows 11 Pro 24H2
• Eclipse IDE/Platform version (as shown in Help > About): Version: 2026-03 (4.39.0). Build id: 20260305-0817
• Java: bundled with eclipse: eclipse/plugins/org.eclipse.justj.openjdk.hotspot.jre.full.win32.x86_64_21.0.10.v20260205-0638\jre
• Maven: bundled with eclipse: 3.9.12/3.9.1200.20260112-2306

Community

• [✓] I understand reporting an issue to this OSS project does not mandate anyone to fix it. Other contributors may consider the issue, or not, at their own convenience. The most efficient way to get it fixed is that I fix it myself and contribute it back as a good quality patch to the project.