Eclipse Formatter settings for comment length ignored

[RLThomaz]

I have a custom, Eclipse Formatter XML preference file that includes the following Eclipse JDT formatter setting for comment length:

<setting id="org.eclipse.jdt.core.formatter.comment.line_length" value="120"/>

I have noticed that, when formatting the code using this settings, comments were always formatted to 80 columns, regardless of the value used. When opening > Java: Open Java Formatter Settings with Preview using the Command Palette, and navigating to the comment section, I noticed that the value in Maximum comment line length is set to 80 -- check out the image below. When modifying this value, my XML file is updated to include the following setting:

<setting id="comment_line_length" value="120"/>

It seems that the formatter is picking up its default setting for line length, which is a property name different than the Eclipse JDT Core formatter setting.

Environment

• Operating System: Amazon Linux 2 (running through SSH)
• JDK version: 8
• Visual Studio Code version: the latest (Nov 2023 release)
• Java extension version: v1.24.0

Steps To Reproduce

1. Create an Eclipsed Formatter XML file containing the setting org.eclipse.jdt.core.formatter.comment.line_length with a value different than 80.
2. Write a comment that goes over 80 or the value set for the property above.
3. Format the code and see the comment being limited to 80 despite the value used in the property above.

Current Result

Comments are formatted to the default value set by comment_line_length instead of the value set by org.eclipse.jdt.core.formatter.comment.line_length.

Expected Result

Comments should be formatted using org.eclipse.jdt.core.formatter.comment.line_length when available.

Additional Informations

Likely related to #2798

[rgrunber]

Where does the java.format.settings.url setting point to ? Is it the location of your custom file, or some other xml formatter file within your project folder ? I noticed there are 2 options :

• Java: Open Java Formatter Settings with Preview
• Java: Open Java Formatter Settings

One creates an eclipse-formatter.xml at the root of the proejct and the other creates a .vscode/java-formatter.xml. Maybe you're editing one of those while the other is being used ?

[RLThomaz]

Where does the java.format.settings.url setting point to ?

It's pointing to my custom file, e.g.:

"java.format.settings.url": "/home/rlthomaz/workplace/ServiceABuildConfiguration/formatter/custom.formatter.preferences.xml",

Yes, there are two options there. It creates a file if java.format.settings.url is not pointing to a valid one already. I actually opened the file with both options, and editing the settings using the GUI (with Preview) option reflects automatically on the raw file opened with the first option.

Maybe you're editing one of those while the other is being used?

I don't think that's the case as I can see changes reflected on my custom file, e.g., editing Blank Lines > Between class declarations to 3 from 1 changes my custom file setting to:

<setting id="org.eclipse.jdt.core.formatter.blank_lines_between_type_declarations" value="3"/>

I have noticed other discrepancies now, though. Editing Indentation > Tab size. from 4 to 8, for example, does not reflect on my custom file. Instead, it updates my *.code-workspace file by including the following JSON object:

		"[java]": {
			"editor.tabSize": 8
		},

I guess this means that the use of *.xml preferences file is inconsistent and only certain Eclipse settings are truly used.

[rgrunber]

I think this might be an issue with vscode-java-pack. The abbreviated setting comment_line_length, isn't generated by vscode-java or the basic formatter functionality. It might be generated by https://github.com/microsoft/vscode-java-pack/blob/f668c69d4027017a534d91961dc55fe31b091e8a/src/formatter-settings/FormatterConstants.ts#L633-L642 . However, even when I use it, it seems to be ignored.

I would try to just generate the settings using https://help.eclipse.org/latest/index.jsp?topic=%2Forg.eclipse.jdt.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fjdt%2Fcore%2Fformatter%2FDefaultCodeFormatterConstants.html .

Update: Actually, maybe I should try playing with a workspace defined by a .code-workspace file, since it seems you may have had that.

[pmouraguedes]

I have the same issue in neovim:

config

<setting id="org.eclipse.jdt.core.formatter.lineSplit" value="120" />

code example 1

// Supressing checkstyle warning. It's a constructor using injection. Not used by programmers (except maybe tests).
public class Main {

    // Supressing checkstyle warning. It's a constructor using injection. Not used
    // by
    public static void main(String[] args) {
    }
}

The interesting things is that the first comment is not affected at all, regardless of the setting.
The second comment is affected but only for values < 80. If I set it e.g. to 20, it will look like this:

config

<setting id="org.eclipse.jdt.core.formatter.lineSplit" value="20" />

code example 2

// Supressing checkstyle warning. It's a constructor using injection. Not used by programmers (except maybe tests).
public class Main {

    // Supressing
    // checkstyle
    // warning. It's
    // a constructor
    // using
    // injection.
    // Not used
    // by
    public static void main(String[] args)
    {
    }
}

But it does not honor values above 80, it always looks like in the first example.

[rgrunber]

I don't think org.eclipse.jdt.core.formatter.lineSplit is meant for comments. There is org.eclipse.jdt.core.formatter.comment.line_length for that. It's mentioned in https://help.eclipse.org/latest/index.jsp?topic=%2Forg.eclipse.jdt.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fjdt%2Fcore%2Fformatter%2FDefaultCodeFormatterConstants.html . Does that help ?

[rgrunber]

I found the problem.

You need org.eclipse.jdt.core.formatter.comment.format_header which is the

Option to control whether the header comment of a Java source file is formatted

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<profiles version="23">
    <profile kind="CodeFormatterProfile" name="test" version="23">
        <setting id="org.eclipse.jdt.core.formatter.comment.line_length" value="50" />
        <setting id="org.eclipse.jdt.core.formatter.comment.format_header" value="true" />
    </profile>
</profiles>

Screencast.From.2025-05-23.10-14-57.mp4