diff --git a/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/ConvertLambdaToMethodReferenceFixCore.java b/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/ConvertLambdaToMethodReferenceFixCore.java
index 9a847531afb..63195b7986f 100644
--- a/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/ConvertLambdaToMethodReferenceFixCore.java	
+++ b/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/ConvertLambdaToMethodReferenceFixCore.java	
@@ -372,7 +372,9 @@ private ASTNode castMethodRefIfNeeded(final CompilationUnitRewrite cuRewrite, AS
 					while (parentTypeBinding != null) {
 						IMethodBinding[] parentTypeMethods= parentTypeBinding.getDeclaredMethods();
 						for (IMethodBinding parentTypeMethod : parentTypeMethods) {
-							if (parentTypeMethod.getName().equals(parentBinding.getName()) && !parentTypeMethod.isEqualTo(parentBinding)) {
+							if (parentTypeMethod.getName().equals(parentBinding.getName())
+									&& parentTypeMethod.getParameterTypes().length == args.size()
+									&& !parentTypeMethod.isEqualTo(parentBinding)) {
 								needCast= true;
 								break;
 							}
diff --git a/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/LambdaExpressionAndMethodRefFixCore.java b/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/LambdaExpressionAndMethodRefFixCore.java
index 15bdc0ea007..7e57142be1f 100644
--- a/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/LambdaExpressionAndMethodRefFixCore.java	
+++ b/org.eclipse.jdt.core.manipulation/core extension/org/eclipse/jdt/internal/corext/fix/LambdaExpressionAndMethodRefFixCore.java	
@@ -479,7 +479,9 @@ private ASTNode castMethodRefIfNeeded(final CompilationUnitRewrite cuRewrite, AS
 					while (parentTypeBinding != null) {
 						IMethodBinding[] parentTypeMethods= parentTypeBinding.getDeclaredMethods();
 						for (IMethodBinding parentTypeMethod : parentTypeMethods) {
-							if (parentTypeMethod.getName().equals(parentBinding.getName()) && !parentTypeMethod.isEqualTo(parentBinding)) {
+							if (parentTypeMethod.getName().equals(parentBinding.getName())
+									&& parentTypeMethod.getParameterTypes().length == args.size()
+									&& !parentTypeMethod.isEqualTo(parentBinding)) {
 								needCast= true;
 								break;
 							}
diff --git a/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/AssistQuickFixTest1d8.java b/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/AssistQuickFixTest1d8.java
index bb50449a157..8a2cf14b372 100644
--- a/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/AssistQuickFixTest1d8.java
+++ b/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/AssistQuickFixTest1d8.java
@@ -5349,6 +5349,59 @@ void test() {
 		assertExpectedExistInProposals(proposals, new String[] { expected1 });
 	}
 
+	@Test
+	public void testIssue1047_5() throws Exception {
+		IPackageFragment pack1= fSourceFolder.createPackageFragment("test1", false, null);
+		String str= """
+			package test1;
+			import java.util.function.Supplier;
+
+			public class E1 {
+			    public static void func( String ... args) {
+			    }
+			    private void called( Supplier<Object> r ) {
+			    }
+
+			}
+			""";
+		pack1.createCompilationUnit("E1.java", str, false, null);
+
+		String str1= """
+			package test1;
+
+			public class E extends E1 {
+
+			    void called( Runnable r, int i ) {
+			    }
+
+			    void test() {
+			        called(() -> E1.func(), 3);
+			    }
+			}
+			""";
+		ICompilationUnit cu= pack1.createCompilationUnit("E.java", str1, false, null);
+
+		int offset= str1.indexOf("func()");
+		AssistContext context= getCorrectionContext(cu, offset, 0);
+		assertNoErrors(context);
+		List<IJavaCompletionProposal> proposals= collectAssists(context, false);
+		assertCorrectLabels(proposals);
+		String expected1= """
+			package test1;
+
+			public class E extends E1 {
+
+			    void called( Runnable r, int i ) {
+			    }
+
+			    void test() {
+			        called(E1::func, 3);
+			    }
+			}
+			""";
+		assertExpectedExistInProposals(proposals, new String[] { expected1 });
+	}
+
 	@Test
 	public void testFixParenthesesInLambdaExpressionAdd() throws Exception {
 		IPackageFragment pack1= fSourceFolder.createPackageFragment("test1", false, null);
diff --git a/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/CleanUpTest1d8.java b/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/CleanUpTest1d8.java
index 6d3073e17ff..62f2a0eaf1e 100644
--- a/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/CleanUpTest1d8.java
+++ b/org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/CleanUpTest1d8.java
@@ -959,6 +959,77 @@ default void m() {
 		assertRefactoringResultAsExpected(new ICompilationUnit[] { cu1 }, new String[] { original }, null);
 	}
 
+	@Test
+	public void testConvertToLambdaAmbiguous04() throws Exception {
+		IPackageFragment pack1= fSourceFolder.createPackageFragment("test", false, null);
+		String sample= """
+			package test;
+			public interface E {
+			    default void m() {
+			        bar(0, new FI() {
+			            @Override
+			            public int foo(int x) {
+			                return x++;
+			            }
+			        }, 3);
+			        baz(0, new ZI() {
+			            @Override
+			            public int zoo() {
+			                return 1;
+			            }
+			        });
+			    }
+
+			    void bar(int i, FI fi, int j);
+			    void bar(int i, FV fv);
+
+			    void baz(int i, ZI zi);
+			    void baz(int i, ZV zv);
+			}
+
+			@FunctionalInterface interface FI { int  foo(int a); }
+			@FunctionalInterface interface FV { void foo(int a); }
+
+			@FunctionalInterface interface ZI { int  zoo(); }
+			@FunctionalInterface interface ZV { void zoo(); }
+			""";
+		String original= sample;
+		ICompilationUnit cu1= pack1.createCompilationUnit("E.java", original, false, null);
+
+		enable(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
+		enable(CleanUpConstants.USE_LAMBDA);
+
+		sample= """
+			package test;
+			public interface E {
+			    default void m() {
+			        bar(0, x -> x++, 3);
+			        baz(0, () -> 1);
+			    }
+
+			    void bar(int i, FI fi, int j);
+			    void bar(int i, FV fv);
+
+			    void baz(int i, ZI zi);
+			    void baz(int i, ZV zv);
+			}
+
+			@FunctionalInterface interface FI { int  foo(int a); }
+			@FunctionalInterface interface FV { void foo(int a); }
+
+			@FunctionalInterface interface ZI { int  zoo(); }
+			@FunctionalInterface interface ZV { void zoo(); }
+			""";
+		String expected1= sample;
+
+		assertRefactoringResultAsExpected(new ICompilationUnit[] { cu1 }, new String[] { expected1 }, null);
+
+		disable(CleanUpConstants.USE_LAMBDA);
+		enable(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION);
+
+		assertRefactoringResultAsExpected(new ICompilationUnit[] { cu1 }, new String[] { original }, null);
+	}
+
 	@Test
 	public void testConvertToLambdaConflictingNames() throws Exception {
 		IPackageFragment pack1= fSourceFolder.createPackageFragment("test", false, null);
@@ -2201,6 +2272,62 @@ void test() {
 				new HashSet<>(Arrays.asList(MultiFixMessages.LambdaExpressionAndMethodRefCleanUp_description)));
 	}
 
+	@Test
+	public void testIssue1047_5() throws Exception {
+		// Given
+		IPackageFragment pack= fSourceFolder.createPackageFragment("test1", false, null);
+		String given1= """
+			import java.util.function.Supplier;
+
+			public class E1 {
+
+			    static void func( String ... args) {
+
+			    }
+			    void called( Supplier<Object> r ) {
+
+			    }
+			}
+			"""; //
+		ICompilationUnit cu1= pack.createCompilationUnit("E1.java", given1, false, null);
+
+		String given= """
+			import java.util.function.Supplier;
+
+			public class E extends E1 {
+
+			    void called( Runnable r, int i ) {
+
+			    }
+			    void test() {
+			        called(() -> E1.func(), 3);
+			    }
+			}
+			"""; //
+
+		String expected= """
+			import java.util.function.Supplier;
+
+			public class E extends E1 {
+
+			    void called( Runnable r, int i ) {
+
+			    }
+			    void test() {
+			        called(E1::func, 3);
+			    }
+			}
+			"""; //
+		// When
+		ICompilationUnit cu= pack.createCompilationUnit("E.java", given, false, null);
+		enable(CleanUpConstants.SIMPLIFY_LAMBDA_EXPRESSION_AND_METHOD_REF);
+
+		// Then
+		assertNotEquals("The class must be changed", given, expected);
+		assertRefactoringResultAsExpected(new ICompilationUnit[] { cu, cu1 }, new String[] { expected, given1 },
+				new HashSet<>(Arrays.asList(MultiFixMessages.LambdaExpressionAndMethodRefCleanUp_description)));
+	}
+
 	@Test
 	public void testBug579393() throws Exception {
 		// Given