Update configuration for copyright headers to use "<year>-present" pattern

Historically, we have used `<introduction year>-<modification year>` as
the pattern for copyright headers.

For example: `Copyright 2002-2025 the original author or authors.`

However, we have been encouraged to use `present` as the modification
year.

In light of that, this commit updates the following to enforce the new
pattern.

- The patterns in our SpringHeaderCheck Checkstyle rules
- The `Copyright 2002-${year}` template in org.eclipse.jdt.ui.prefs
- The update_copyright_headers.sh script

See gh-35070

buildSrc/config/checkstyle/checkstyle.xml

@@ -6,7 +6,7 @@
 	<module name="io.spring.javaformat.checkstyle.check.SpringHeaderCheck">
 		<property name="fileExtensions" value="java"/>
 		<property name="headerType" value="apache2"/>
-		<property name="headerCopyrightPattern" value="20\d\d-20\d\d"/>
+		<property name="headerCopyrightPattern" value="20\d\d-present"/>
 		<property name="packageInfoHeaderType" value="none"/>
 	</module>
 	<module name="com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck"/>

src/checkstyle/checkstyle.xml

@@ -11,7 +11,7 @@
 	<module name="io.spring.javaformat.checkstyle.check.SpringHeaderCheck">
 		<property name="fileExtensions" value="java"/>
 		<property name="headerType" value="apache2"/>
-		<property name="headerCopyrightPattern" value="20\d\d-20\d\d"/>
+		<property name="headerCopyrightPattern" value="20\d\d-present"/>
 		<property name="packageInfoHeaderType" value="none"/>
 	</module>
 	<module name="com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck"/>

update_copyright_headers.sh

@@ -1,21 +1,16 @@
 #!/bin/sh
 #
 # This shell script updates the copyright headers in source code files
-# in the current branch that have been added or modified during the
-# current year (at least as much as the `git diff` command supports the
-# date range in terms of log history).
+# in the current branch so that the headers conform to the pattern:
+# <start-year>-present.
+# 
+# For example, "Copyright 2002-2025" will be replaced with
+# "Copyright 2002-current".
 #
 # This has only been tested on mac OS.
 
-current_year=$(date +'%Y')
-echo Updating copyright headers in Java, Kotlin, and Groovy source code for year $current_year
+echo Updating copyright headers in Java, Kotlin, and Groovy source code
 
-# Added/Modified this year and committed
-for file in $(git --no-pager diff --name-only --diff-filter=AM @{$current_year-01-01}..@{$current_year-12-31} | egrep "^.+\.(java|kt|groovy)$" | uniq); do
-	sed -i '' -E "s/Copyright 2002-[0-9]{4}/Copyright 2002-$current_year/g" $file;
-done
-
-# Added/Modified and staged but not yet committed
-for file in $(git --no-pager diff --name-only --diff-filter=AM --cached | egrep "^.+\.(java|kt|groovy)$" | uniq); do
-	sed -i '' -E "s/Copyright 2002-[0-9]{4}/Copyright 2002-$current_year/g" $file;
+for file in $(find -E . -type f -regex '.+\.(java|kt|groovy)$' | uniq); do
+	sed -i '' -E "s/Copyright ([0-9]{4})-[0-9]{4}/Copyright \1-present/g" $file;
 done