Fix overridden method inherited javadoc when markdown is used

org.eclipse.jdt.core.manipulation/common/org/eclipse/jdt/core/manipulation/internal/javadoc/CoreJavadocAccess.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2023 IBM Corporation and others.
+ * Copyright (c) 2008, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -433,7 +433,39 @@ protected String javadoc2HTML(IMember member, IJavaElement element, String rawJa
 		}
 
 		if (CoreJavadocContentAccessUtility.canInheritJavadoc(member)) {
-			IMethod method= (IMethod) member;
+			IMethod method= (IMethod)member;
+			IType declaringType= method.getDeclaringType();
+
+			IMethod overridden= null;
+			if (rawJavadoc.equals("/***/")) { //$NON-NLS-1$
+				try {
+					// we have assumed we have old-style Javadoc...check if
+					// we have an overridden method with Javadoc where we can check if
+					// it is markdown in which case, update rawJavadoc string and
+					// recalculate javadoc based on using a markdown processor
+					if (!method.isConstructor()) {
+						ITypeHierarchy hierarchy= SuperTypeHierarchyCache.getTypeHierarchy(declaringType);
+						MethodOverrideTester tester= new MethodOverrideTester(declaringType, hierarchy);
+						overridden= tester.findOverriddenMethod(method, true);
+					}
+					if (overridden != null) {
+						IBuffer buf= overridden.getOpenable().getBuffer();
+						if (buf != null) {
+							ISourceRange javadocRange= overridden.getJavadocRange();
+							if (javadocRange != null) {
+								String javadocStart= buf.getText(javadocRange.getOffset(), 3);
+								if (javadocStart.equals("///")) { //$NON-NLS-1$
+									rawJavadoc= "///\n"; //$NON-NLS-1$
+									javadoc= CoreJavadocContentAccessUtility.getJavadocNode(member, rawJavadoc);
+								}
+							}
+						}
+					}
+				} catch (JavaModelException e2) {
+					JavaManipulationPlugin.log(e2);
+				}
+			}
+
 			return this.fFactory.createJavadocAccess(element, javadoc, rawJavadoc, new JavadocLookup(method.getDeclaringType(), this.fFactory)).toHTML();
 		}
 		return this.fFactory.createJavadocAccess(element, javadoc, rawJavadoc, null).toHTML();

org.eclipse.jdt.core.manipulation/common/org/eclipse/jdt/core/manipulation/internal/javadoc/CoreJavadocAccessImpl.java

@@ -578,7 +578,7 @@ public CharSequence getMainDescription() {
 
 			fBuf= null;
 		}
-		return fMainDescription.length() > 0 ? fMainDescription : null;
+		return fMainDescription.length() > 0 ? fMainDescription.append("\n") : null; //$NON-NLS-1$
 	}
 
 	@Override

org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/hover/MarkdownCommentTests.java

@@ -16,6 +16,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.net.URI;
@@ -505,8 +506,8 @@ public void m(int i) {}
 		String superURI= makeEncodedClassUri("p", "Spec03Tags", "Super");
 		String superMURI= makeEncodedMethodUri(true, "p", "Spec03Tags", "Super","m", "I");
 		String expectedContent= """
-				<p>super doc
-				In addition, this methods calls <code><a href='METHOD_URI'>wait()</a></code>.<div><b>Overrides:</b> <a href='SUPER_M_URI'>m(...)</a> in <a href='SUPER_URI'>Super</a></div></p>
+				<p>super doc</p>
+				<p>In addition, this methods calls <code><a href='METHOD_URI'>wait()</a></code>.<div><b>Overrides:</b> <a href='SUPER_M_URI'>m(...)</a> in <a href='SUPER_URI'>Super</a></div></p>
 				<dl><dt>Parameters:</dt><dd><b>i</b> the index</dd></dl>
 				"""
 				.replace("METHOD_URI", waitURI)
@@ -1114,4 +1115,39 @@ public class Markdown {}
 		assertEquals("sequence doesn't match", expectedContent, actualSnippet);
 	}
 
+	@Test
+	public void testInheritedMethod() throws CoreException {
+		String source= """
+				public class Base {
+				    /// ## Title
+				    /// *Some* `formatted` {@code text}
+				    /// ```
+				    /// block
+				    /// ```
+				    ///
+				    void m() {}
+
+				    class A1 extends Base {
+				        @Override
+				        void m() {}
+				    }
+				}
+				""";
+		ICompilationUnit cu= getWorkingCopy("/TestSetupProject/src/p/Base.java", source, null);
+		assertNotNull("Base.java", cu);
+
+		String expectedContent= """
+				<p><em>Some</em> <code>formatted</code> <code>text
+				</code></p>
+				<pre><code>block
+				</code></pre>
+				<div><b>Overrides:</b> <a href='eclipse-javadoc:%E2%98%82=TestSetupProject/src%3Cp%7BBase.java%E2%98%83Base~m'>m()</a> in <a href='eclipse-javadoc:%E2%98%82=TestSetupProject/src%3Cp%7BBase.java%E2%98%83Base'>Base</a></div>
+				""";
+		IType type0= cu.getType("Base");
+		IType type= type0.getType("A1");
+		IMethod method= type.getMethods()[0];
+		String actualHtmlContent= getHoverHtmlContent(cu, method);
+		assertTrue("Doesn't contain expected content", actualHtmlContent.contains(expectedContent));
+	}
+
 }