java formatter: unable to wrap/break long Strings

[reuschling]

I come from Intellij idea and I'm used to break long lines with the formatter. I managed to export/import most of the settings, but I can not manage it that vscode breaks long String lines, splitting the Strings with "firstPart" + "secondPart".

These are my related settings in the codeFormatterSettings.json:

<setting id="org.eclipse.jdt.core.formatter.lineSplit" value="180"/>
<setting id="org.eclipse.jdt.core.formatter.formatter_wrap_long_strings" value="true"/>
<setting id="org.eclipse.jdt.core.formatter.wrap_strings" value="true"/>
<setting id="org.eclipse.jdt.core.formatter.wrap_before_string_concatenation" value="true"/>

Please ask if I should upload the whole file.

This is an example line of code:

String strSystemPrompt =
                "You are a system that generates a concise and informative answer in less than 100 words for the given question, which is marked with QUESTION. Use the given search results marked with SEARCH RESULT as only knowledge base. Answer questions in the language of the question, i.e. german questions in german and only english questions in english.";

This is the expected output:

String strSystemPrompt =
                "You are a system that generates a concise and informative answer in less than 100 words for the given question, which is marked with QUESTION. Use the given search" + 
                "results marked with SEARCH RESULT as only knowledge base. Answer questions in the language of the question, i.e. german questions in german and only english" + 
                "questions in english.";

Am I missing something, is it not supported, or is it a bug?

VSCode version 1.98.2
Java Language support:
Version
1.40.0
Last Updated
2025-03-06, 08:33:26

[rgrunber]

I think the problem here is that converting a single string to a set of string concatenations to wrap the line is technically not a format operation, but more of a code change. The job of the formatter is not really to introduce changes to the source code like that. I agree it could be useful maybe even as a code action though. If there was something like :

String strSystemPrompt = "You" + "are" + "a" + "system" + "that" + "generates" + "a" + "concise" + "and" + "informative" + "answer" + "in" + "less" + "than" + "100" + "words" + "for" + "the" + "given" + "question," + "which" + "is" + "marked" + "with" + "QUESTION." + "Use" + "the" + "given" + "search" + "results" + "marked" + "with" + "SEARCH" + "RESULT" + "as" + "only" + "knowledge" + "base." + "Answer" + "questions" + "in" + "the" + "language" + "of" + "the" + "question," + "i.e." + "german" + "questions" + "in" + "german" + "and" + "only" + "english" + "questions" + "in" + "english.";

then that would work (I set lineSplit for 80):

Screencast.From.2025-03-25.13-20-30.mp4

We have a few operations we introduced to convert between string concatentation, StringBuffer, String.format(), and text blocks, so perhaps what we're missing is some kind of code action to wrap long strings that respects the lineSplit setting.