Eclipse：变量的调试和检查导致 com.sun.jdi.ObjectCollectedException

Question

I debug my program and add here and there a breakpoint. After a stop I want to inspect some of the variables and get sometimes a com.sun.jdi.ObjectCollectedException . After searching in different sources I figured out that most likely the object was G arbage C ollected. Clicking here and there I could retrieve my object by nevertheless in the Variables view I cannot inspect the variable.

-vmargs
-Dosgi.requiredJavaVersion=1.8
-Dosgi.instance.area.default=@user.home/eclipse-workspace
-XX:+UseG1GC
-XX:+UseStringDeduplication
--add-modules=ALL-SYSTEM
-Dosgi.requiredJavaVersion=1.8
-Xms512m
-Xmx4096m
--add-modules=ALL-SYSTEM

I'm running under Linux/OpenSuSe with OpenJDK 1.8.0_151. Any hints how to avoid that kind of GC problems? Is this some kind of setting in the IDE?

Answer 1

Right click the variable, then click "Show Logical Structure", uncheck any collection.

Answer 2

While execution of your code is stopped at a breakpoint:

1. Right-click the variable in the Variables pane
2. Clicking on the collections (such as the Array in the image below) will uncheck them
3. Now you can inspect the variable

Answer 3

This bug has been fixed in Eclipse 4.18

https://www.eclipse.org/eclipse/news/4.18/jdt.php

Stabilized logical structures in Variables view with active GC

The Debug view no longer breaks when logical structures are shown while the application's garbage collector is active (com.sun.jdi.ObjectCollectedException occurred while retrieving value).

Answer 4

Instead of turning off logical structure, you can add a logical structure formatter, as detailed in this answer: Eclipse debug mode view instance variable values . This prevents the exception and lets you see the variable in a useful way.