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8360575: java.util.Properties.list() methods trim each value to 37 characters in the listed output #26018

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8360575: java.util.Properties.list() methods trim each value to 37 characters in the listed output #26018

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8360575: java.util.Properties.list() methods trim each value to 37 ch…
jaikiran Jun 27, 2025
d276ad0
Alan's review - limit the details in implNote
jaikiran Jun 27, 2025
049e43e
Andy's review suggestions
jaikiran Jun 27, 2025
df9c7ca
Alan's review - no need to state the number of characters
jaikiran Jun 30, 2025
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34 changes: 29 additions & 5 deletions src/java.base/share/classes/java/util/Properties.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1995, 2024, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1995, 2025, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -1211,10 +1211,22 @@ public Set<String> stringPropertyNames() {
}

/**
* Prints this property list out to the specified output stream.
* Prints this property list out to the specified {@link PrintStream}.
* This method is useful for debugging.
*
* @param out an output stream.
* @implNote If any property's value is greater than 40 characters then
* this method writes only the first 37 characters of that value
* followed by 3 dot characters.
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I don't think the note needs to that specific. I think it need only say that the implementation truncates the output for very long property values.

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Hello Alan, I think not noting the character count which determines the truncation would lead to questions about what "very long property values" are. However, this is a method which is specified to be for debug purposes only and I see that there's a suggestion to deprecate these methods. So I have gone ahead and updated this text to follow your suggestion. I'll respond to the deprecation proposal separately in this PR.

* <p>
* An alternative for listing the {@code Properties} to a {@code PrintStream} is:
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suggestion:
``
An alternative for listing the {@code Properties} to a {@code PrintStream} without truncation is:

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Good point. I've now updated the PR with this text.

* {@snippet lang=java :
* Properties p = ...
* PrintStream out = ...
* // list the properties to PrintStream
* p.forEach((k, v) -> out.println(k + "=" + v));
* }
*
* @param out a PrintStream
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suggestion: (here and L1263) "the output PrintStream"

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Done

* @throws ClassCastException if any key in this property list
* is not a string.
*/
Expand All @@ -1233,10 +1245,22 @@ public void list(PrintStream out) {
}

/**
* Prints this property list out to the specified output stream.
* Prints this property list out to the specified {@link PrintWriter}.
* This method is useful for debugging.
*
* @param out an output stream.
* @implNote If any property's value is greater than 40 characters then
* this method writes only the first 37 characters of that value
* followed by 3 dot characters.
* <p>
* An alternative for listing the {@code Properties} to a {@code PrintWriter} is:
* {@snippet lang=java :
* Properties p = ...
* PrintWriter out = ...
* // list the properties to PrintWriter
* p.forEach((k, v) -> out.println(k + "=" + v));
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Should our example recommend using toString as a utility to obtain a debug string instead, as it performs no truncation?

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Using toString() will be harder to read; as proposed each property is on a separate line.

* }
*
* @param out a PrintWriter
* @throws ClassCastException if any key in this property list
* is not a string.
* @since 1.1
Expand Down