Check if Eclipse 4.23 (Feb. 2022, 7 years later) could help:

The Run/Debug preference page now shows a new option to allow to show debug values inline.

When enabled, this will print debug values as a code minings annotation on the end of line.
The values shown would then react to change in the debug context as you navigate through the execution.

This is an experimental feature and as this requires extra effort for the debuggers to enable it, not all debuggers may support it yet.

To be activated with the preference:

As noted by gillesB in the comments in 2022:

It is worth to mention that the Java debugger does not yet support this feature.