diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileWrapperTests.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileWrapperTests.java
index aa7dd0be42..83482dbcd3 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileWrapperTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileWrapperTests.java
@@ -19,18 +19,25 @@ package org.springframework.boot.loader.jar;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.MalformedURLException;
+import java.net.URL;
+import java.security.Permission;
+import java.util.EnumSet;
+import java.util.Enumeration;
+import java.util.Set;
 import java.util.jar.JarOutputStream;
+import java.util.jar.Manifest;
 import java.util.zip.ZipEntry;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
+import org.springframework.boot.loader.jar.JarFileWrapperTests.SpyJarFile.Call;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.mockito.Mockito.spy;
-import static org.mockito.Mockito.verify;
 
 /**
  * Tests for {@link JarFileWrapper}.
@@ -39,13 +46,13 @@ import static org.mockito.Mockito.verify;
  */
 class JarFileWrapperTests {
 
-	private JarFile parent;
+	private SpyJarFile parent;
 
 	private JarFileWrapper wrapper;
 
 	@BeforeEach
 	void setup(@TempDir File temp) throws IOException {
-		this.parent = spy(new JarFile(createTempJar(temp)));
+		this.parent = new SpyJarFile(createTempJar(temp));
 		this.wrapper = new JarFileWrapper(this.parent);
 	}
 
@@ -58,68 +65,68 @@ class JarFileWrapperTests {
 	@Test
 	void getUrlDelegatesToParent() throws MalformedURLException {
 		this.wrapper.getUrl();
-		verify(this.parent).getUrl();
+		this.parent.verify(Call.GET_URL);
 	}
 
 	@Test
 	void getTypeDelegatesToParent() {
 		this.wrapper.getType();
-		verify(this.parent).getType();
+		this.parent.verify(Call.GET_TYPE);
 	}
 
 	@Test
 	void getPermissionDelegatesToParent() {
 		this.wrapper.getPermission();
-		verify(this.parent).getPermission();
+		this.parent.verify(Call.GET_PERMISSION);
 	}
 
 	@Test
 	void getManifestDelegatesToParent() throws IOException {
 		this.wrapper.getManifest();
-		verify(this.parent).getManifest();
+		this.parent.verify(Call.GET_MANIFEST);
 	}
 
 	@Test
 	void entriesDelegatesToParent() {
 		this.wrapper.entries();
-		verify(this.parent).entries();
+		this.parent.verify(Call.ENTRIES);
 	}
 
 	@Test
 	void getJarEntryDelegatesToParent() {
 		this.wrapper.getJarEntry("test");
-		verify(this.parent).getJarEntry("test");
+		this.parent.verify(Call.GET_JAR_ENTRY);
 	}
 
 	@Test
 	void getEntryDelegatesToParent() {
 		this.wrapper.getEntry("test");
-		verify(this.parent).getEntry("test");
+		this.parent.verify(Call.GET_ENTRY);
 	}
 
 	@Test
 	void getInputStreamDelegatesToParent() throws IOException {
 		this.wrapper.getInputStream();
-		verify(this.parent).getInputStream();
+		this.parent.verify(Call.GET_INPUT_STREAM);
 	}
 
 	@Test
 	void getEntryInputStreamDelegatesToParent() throws IOException {
 		ZipEntry entry = new ZipEntry("test");
 		this.wrapper.getInputStream(entry);
-		verify(this.parent).getInputStream(entry);
+		this.parent.verify(Call.GET_ENTRY_INPUT_STREAM);
 	}
 
 	@Test
 	void getCommentDelegatesToParent() {
 		this.wrapper.getComment();
-		verify(this.parent).getComment();
+		this.parent.verify(Call.GET_COMMENT);
 	}
 
 	@Test
 	void sizeDelegatesToParent() {
 		this.wrapper.size();
-		verify(this.parent).size();
+		this.parent.verify(Call.SIZE);
 	}
 
 	@Test
@@ -137,4 +144,117 @@ class JarFileWrapperTests {
 				.isThrownBy(() -> JarFileWrapper.class.getDeclaredMethod("close"));
 	}
 
+	/**
+	 * {@link JarFile} that we can spy (even on Java 11+)
+	 */
+	static class SpyJarFile extends JarFile {
+
+		private final Set<Call> calls = EnumSet.noneOf(Call.class);
+
+		SpyJarFile(File file) throws IOException {
+			super(file);
+		}
+
+		@Override
+		Permission getPermission() {
+			mark(Call.GET_PERMISSION);
+			return super.getPermission();
+		}
+
+		@Override
+		public Manifest getManifest() throws IOException {
+			mark(Call.GET_MANIFEST);
+			return super.getManifest();
+		}
+
+		@Override
+		public Enumeration<java.util.jar.JarEntry> entries() {
+			mark(Call.ENTRIES);
+			return super.entries();
+		}
+
+		@Override
+		public JarEntry getJarEntry(String name) {
+			mark(Call.GET_JAR_ENTRY);
+			return super.getJarEntry(name);
+		}
+
+		@Override
+		public ZipEntry getEntry(String name) {
+			mark(Call.GET_ENTRY);
+			return super.getEntry(name);
+		}
+
+		@Override
+		InputStream getInputStream() throws IOException {
+			mark(Call.GET_INPUT_STREAM);
+			return super.getInputStream();
+		}
+
+		@Override
+		InputStream getInputStream(String name) throws IOException {
+			mark(Call.GET_ENTRY_INPUT_STREAM);
+			return super.getInputStream(name);
+		}
+
+		@Override
+		public String getComment() {
+			mark(Call.GET_COMMENT);
+			return super.getComment();
+		}
+
+		@Override
+		public int size() {
+			mark(Call.SIZE);
+			return super.size();
+		}
+
+		@Override
+		public URL getUrl() throws MalformedURLException {
+			mark(Call.GET_URL);
+			return super.getUrl();
+		}
+
+		@Override
+		JarFileType getType() {
+			mark(Call.GET_TYPE);
+			return super.getType();
+		}
+
+		private void mark(Call call) {
+			this.calls.add(call);
+		}
+
+		void verify(Call call) {
+			assertThat(call).matches(this.calls::contains);
+		}
+
+		enum Call {
+
+			GET_URL,
+
+			GET_TYPE,
+
+			GET_PERMISSION,
+
+			GET_MANIFEST,
+
+			ENTRIES,
+
+			GET_JAR_ENTRY,
+
+			GET_ENTRY,
+
+			GET_INPUT_STREAM,
+
+			GET_ENTRY_INPUT_STREAM,
+
+			GET_COMMENT,
+
+			SIZE
+
+		}
+
+	}
+
 }