8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args #25881

prrace · 2025-06-18T17:57:26Z

Clarify the behaviour of new HeadlessException().getMessage()
The spec. is updated to be clear that empty means null, not an empty string.

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Change requires CSR request JDK-8359951 to be approved

Issues

JDK-8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args (Bug - P2)
JDK-8359951: Clarify behavior of java.awt.HeadlessException constructed with no-args (CSR)

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Alexey Ivanov (@aivanov-jdk - Reviewer)
Harshitha Onkar (@honkar-jdk - Reviewer)

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prrace · 2025-06-18T17:57:39Z

/csr

bridgekeeper · 2025-06-18T17:58:13Z

👋 Welcome back prr! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2025-06-18T17:58:53Z

@prrace This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args

Reviewed-by: aivanov, honkar

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 36 new commits pushed to the master branch:

d627282: 8360143: ProblemList runtime/NMT/VirtualAllocTestType.java
96f71a9: 8255082: HotSpot Style Guide should permit noexcept
17cf497: 8357550: GenShen crashes during freeze: assert(!chunk->requires_barriers()) failed
... and 33 more: https://git.openjdk.org/jdk/compare/382f870cd53d69dfc1d2b96150aa2c026e47f642...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

openjdk · 2025-06-18T17:59:51Z

@prrace an approved CSR request is already required for this pull request.

openjdk · 2025-06-18T18:00:32Z

@prrace The following label will be automatically applied to this pull request:

client

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

mlbridge · 2025-06-18T18:04:15Z

Webrevs

00: Full (b1673a47)

prrace · 2025-06-18T18:06:53Z

CSR to be reviewed https://bugs.openjdk.org/browse/JDK-8359951

aivanov-jdk

Should each constructor specify how the message returned by getMessage is constructed instead of directing to the specification of getMessage for details?

aivanov-jdk · 2025-06-18T18:30:04Z

src/java.desktop/share/classes/java/awt/HeadlessException.java

     * For such {@code HeadlessException} the default headless error message
     * may be auto-generated for some platforms.
     * The text of the default headless message may depend on


This doesn't align, the following text has to be modified too.

The first sentence of the second paragraph, “For such {@code HeadlessException} the default headless error message may be auto-generated for some platforms,” should be replaced with the slightly edited text from the HeadlessException(String) constructor: “For some platforms, the {@code null} detail message may be replaced with the default headless error message.”

I don't see why.

prrace · 2025-06-18T22:26:46Z

Should each constructor specify how the message returned by getMessage is constructed instead of directing to the specification of getMessage for details?

100% no. I am not wasting time on that. This whole spec. is getting revamped again in JDK 26 in very short order after this minimal fix is backported to JDK 25

aivanov-jdk · 2025-06-19T09:25:25Z

Should each constructor specify how the message returned by getMessage is constructed instead of directing to the specification of getMessage for details?

100% no. I am not wasting time on that. This whole spec. is getting revamped again in JDK 26 in very short order after this minimal fix is backported to JDK 25

I see, thank you for your clarification.

So, this is a minimal update to the specification to quickly address the problem with null vs. empty message, which is being backported to JDK 25; the specification for JDK 26 is going to be overhauled shortly.

Is my understanding correct now?

prrace · 2025-06-19T17:03:13Z

Should each constructor specify how the message returned by getMessage is constructed instead of directing to the specification of getMessage for details?

100% no. I am not wasting time on that. This whole spec. is getting revamped again in JDK 26 in very short order after this minimal fix is backported to JDK 25

I see, thank you for your clarification.

So, this is a minimal update to the specification to quickly address the problem with null vs. empty message, which is being backported to JDK 25; the specification for JDK 26 is going to be overhauled shortly.

Is my understanding correct now?

Right. What I am obliged to do in order to satisfy one specific TCK test. Nothing more.

aivanov-jdk · 2025-06-19T17:06:18Z

Right. What I am obliged to do in order to satisfy one specific TCK test. Nothing more.

Thank you! It makes perfect sense.

Looks good to me.

alisenchung · 2025-06-20T21:07:22Z

src/java.desktop/share/classes/java/awt/HeadlessException.java

do copyright years need to be updated for this file if there's a docs change?

honkar-jdk

Updated javadoc and regression test LGTM.

prrace · 2025-06-20T22:21:43Z

/integrate

openjdk · 2025-06-20T22:22:45Z

Going to push as commit 81985d4.
Since your change was applied there have been 36 commits pushed to the master branch:

d627282: 8360143: ProblemList runtime/NMT/VirtualAllocTestType.java
96f71a9: 8255082: HotSpot Style Guide should permit noexcept
17cf497: 8357550: GenShen crashes during freeze: assert(!chunk->requires_barriers()) failed
... and 33 more: https://git.openjdk.org/jdk/compare/382f870cd53d69dfc1d2b96150aa2c026e47f642...master

Your commit was automatically rebased without conflicts.

honkar-jdk · 2025-06-20T22:22:53Z

test/jdk/java/awt/Headless/HeadlessExceptionTest.java

+        String nullmsg = new HeadlessException().getMessage();
+        String emptymsg = new HeadlessException("").getMessage();


@prrace I was thinking of a case which would actually throw HeadlessException when run with Djava.awt.headless=true such as creating a frame or robot but the exception msg can be null or default message from GraphicsEnvironment so making it difficult to validate on different platforms. The current test works well to validate both empty and null message.

openjdk · 2025-06-20T22:22:54Z

@prrace Pushed as commit 81985d4.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

8358526

b1673a4

openjdk bot changed the title ~~8358526~~ 8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args Jun 18, 2025

openjdk bot added csr Pull request needs approved CSR before integration rfr Pull request is ready for review labels Jun 18, 2025

openjdk bot added the client [email protected] label Jun 18, 2025

aivanov-jdk suggested changes Jun 18, 2025

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aivanov-jdk approved these changes Jun 19, 2025

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openjdk bot added ready Pull request is ready to be integrated and removed csr Pull request needs approved CSR before integration labels Jun 20, 2025

alisenchung reviewed Jun 20, 2025

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honkar-jdk approved these changes Jun 20, 2025

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openjdk bot added the integrated Pull request has been integrated label Jun 20, 2025

openjdk bot closed this Jun 20, 2025

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Jun 20, 2025

honkar-jdk reviewed Jun 20, 2025

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		String nullmsg = new HeadlessException().getMessage();
		String emptymsg = new HeadlessException("").getMessage();

8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args #25881

8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args #25881

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