Address review feedback: fix regex ReDoS, finally-block state leaks, and typo

- Use possessive quantifiers in META_TAG_PATTERN and META_CHARSET_PATTERN
  to eliminate polynomial backtracking flagged by CodeQL
- Wrap charset reset in try/finally so classpath restoration always
  executes even if setDefaultCharset throws
- Fix remaining 'Shouldhave' typo in testBug426058

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: chagong

org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/AttachedJavadocTests.java

@@ -1096,7 +1096,7 @@ public void testBug394382() throws JavaModelException {
 			} catch(JavaModelException e) {
 				assertTrue("Should not happen", false);
 			}
-			assertNotNull("Shouldhave a javadoc", javadoc); //$NON-NLS-1$
+				assertNotNull("Should have a javadoc", javadoc); //$NON-NLS-1$
 			String encodedContents = new String (Util.getResourceContentsAsCharArray(sourceFile, encoding));
 			char[] charArray = encodedContents.toCharArray();
 			encodedContents = new String(CharOperation.remove(charArray, '\r'));
@@ -1170,7 +1170,7 @@ public void testBug426058() throws Exception {
 			} catch(JavaModelException e) {
 				assertTrue("Should not happen", false);
 			}
-			assertNotNull("Shouldhave a javadoc", javadoc); //$NON-NLS-1$
+			assertNotNull("Should have a javadoc", javadoc); //$NON-NLS-1$
 			String encodedContents = new String (Util.getResourceContentsAsCharArray(sourceFile, encoding));
 			char[] charArray = encodedContents.toCharArray();
 			encodedContents = new String(CharOperation.remove(charArray, '\r'));
@@ -1179,8 +1179,11 @@ public void testBug426058() throws Exception {
 			assertTrue("Sources should be decoded the same way", encodedContents.equals(javadoc));
 		}
 		finally {
-			this.project.getProject().setDefaultCharset(oldEncoding, null);
-			this.project.setRawClasspath(oldClasspath, null);
+			try {
+				this.project.getProject().setDefaultCharset(oldEncoding, null);
+			} finally {
+				this.project.setRawClasspath(oldClasspath, null);
+			}
 		}
 	}
 	public void testAttachedJavadocWithModernMetaCharset() throws Exception {
@@ -1241,8 +1244,11 @@ public void testAttachedJavadocWithModernMetaCharset() throws Exception {
 			assertEquals("Sources should be decoded the same way", encodedContents, javadoc);
 		}
 		finally {
-			this.project.getProject().setDefaultCharset(oldEncoding, null);
-			this.project.setRawClasspath(oldClasspath, null);
+			try {
+				this.project.getProject().setDefaultCharset(oldEncoding, null);
+			} finally {
+				this.project.setRawClasspath(oldClasspath, null);
+			}
 		}
 	}
 	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=403154

org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/JavaElement.java

@@ -63,8 +63,8 @@ public abstract class JavaElement extends PlatformObject implements IJavaElement
 //	private static final QualifiedName PROJECT_JAVADOC= new QualifiedName(JavaCore.PLUGIN_ID, "project_javadoc_location"); //$NON-NLS-1$
 
 	private static final int HTML_HEAD_PREFIX_LENGTH = 4096;
-	private static final Pattern META_TAG_PATTERN = Pattern.compile("<meta\\s+[^>]*>", Pattern.CASE_INSENSITIVE); //$NON-NLS-1$
-	private static final Pattern META_CHARSET_PATTERN = Pattern.compile("(?<![A-Za-z0-9_-])charset\\s*=\\s*([\\\"']?)([^\\s\\\"'/>;]+)\\1", Pattern.CASE_INSENSITIVE); //$NON-NLS-1$
+	private static final Pattern META_TAG_PATTERN = Pattern.compile("<meta\\s[^>]*+>", Pattern.CASE_INSENSITIVE); //$NON-NLS-1$
+	private static final Pattern META_CHARSET_PATTERN = Pattern.compile("(?<![A-Za-z0-9_-])charset\\s*+=\\s*+([\"']?)([^\\s\"'/>;]+)\\1", Pattern.CASE_INSENSITIVE); //$NON-NLS-1$
 	public static final char JEM_ESCAPE = '\\';
 	public static final char JEM_JAVAPROJECT = '=';
 	public static final char JEM_PACKAGEFRAGMENTROOT = '/';