Add Eclipse JDT embedded lockfiles, upgrade formatter version to 4.40

CHANGES.md

@@ -12,6 +12,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ## [Unreleased]
 ### Changes
 - Bump default `greclipse` version to latest `4.39` -> `4.40`. ([#2989](https://github.com/diffplug/spotless/pull/2989))
+- Add embedded lockfiles to Eclipse JDT (4.9, 4.11, 4.39, 4.40), bump version to latest `4.39` -> `4.40`. ([#1996](https://github.com/diffplug/spotless/issues/1996))
 
 ## [4.8.0] - 2026-06-29
 ### Added

lib-extra/src/main/java/com/diffplug/spotless/extra/EquoBasedStepBuilder.java

@@ -18,7 +18,10 @@
 import static java.util.stream.Collectors.toMap;
 
 import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 import java.io.Serializable;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -28,6 +31,7 @@
 
 import javax.annotation.Nullable;
 
+import com.diffplug.common.base.Errors;
 import com.diffplug.common.collect.ImmutableMap;
 import com.diffplug.spotless.FileSignature;
 import com.diffplug.spotless.FormatterFunc;
@@ -122,6 +126,10 @@ protected void addPlatformRepo(P2Model model, String version) {
 	/** Returns the FormatterStep (whose state will be calculated lazily). */
 	public FormatterStep build() {
 		var roundtrippableState = new EquoStep(formatterVersion, settingProperties, settingXml, FileSignature.promise(settingsFiles), JarState.promise(() -> {
+			List<String> lockfileDependencies = readEmbeddedLockfileDependencies(formatterVersion);
+			if (lockfileDependencies != null) {
+				return JarState.from(lockfileDependencies, mavenProvisioner);
+			}
 			P2Model model = createModelWithMirrors();
 			P2ModelWrapper modelWrapper = P2ModelWrapper.wrap(model);
 			List<File> classpath = p2Provisioner.provisionP2Dependencies(modelWrapper, mavenProvisioner, cacheDirectory).stream()
@@ -133,6 +141,56 @@ public FormatterStep build() {
 		return FormatterStep.create(formatterName, roundtrippableState, EquoStep::state, stateToFormatter);
 	}
 
+	@Nullable
+	private List<String> readEmbeddedLockfileDependencies(String version) {
+		String lockfileResourcePath = lockfileResourcePath(version);
+		if (lockfileResourcePath == null) {
+			return null;
+		}
+		if (!lockfileResourcePath.startsWith("/")) {
+			throw new IllegalArgumentException("Lockfile resource path must start with '/': " + lockfileResourcePath);
+		}
+		InputStream lockfile = EquoBasedStepBuilder.class.getResourceAsStream(lockfileResourcePath);
+		if (lockfile == null) {
+			// No lockfile embedded for this version — fall back to P2 provisioning
+			return null;
+		}
+		String allLines;
+		try (lockfile) {
+			allLines = new String(lockfile.readAllBytes(), StandardCharsets.UTF_8);
+		} catch (IOException e) {
+			throw Errors.asRuntime(e);
+		}
+		var dependencies = new ArrayList<String>();
+		for (String line : allLines.split("\n")) {
+			String trimmed = line.trim();
+			if (!trimmed.isEmpty() && !trimmed.startsWith("#")) {
+				dependencies.add(trimmed);
+			}
+		}
+		if (dependencies.isEmpty()) {
+			throw new IllegalArgumentException("No dependencies defined in lockfile " + lockfileResourcePath);
+		}
+		return dependencies;
+	}
+
+	/**
+	 * Returns the classpath resource path of an embedded lockfile for the given formatter version.
+	 * <p>
+	 * The default implementation always returns {@code null}, which means dependency resolution
+	 * falls back to P2 provisioning.
+	 * <p>
+	 * Overriding implementations should return an absolute classpath resource path (starting with
+	 * {@code /}) that is compatible with {@link Class#getResourceAsStream(String)}.
+	 *
+	 * @return absolute classpath resource path of the embedded lockfile, or {@code null} to use
+	 * P2 provisioning
+	 */
+	@Nullable
+	protected String lockfileResourcePath(String version) {
+		return null;
+	}
+
 	private P2Model createModelWithMirrors() {
 		P2Model model = model(formatterVersion);
 		if (p2Mirrors.isEmpty()) {

lib-extra/src/main/java/com/diffplug/spotless/extra/java/EclipseJdtFormatterStep.java

@@ -35,7 +35,7 @@ public final class EclipseJdtFormatterStep {
 	private EclipseJdtFormatterStep() {}
 
 	private static final String NAME = "eclipse jdt formatter";
-	private static final Jvm.Support<String> JVM_SUPPORT = Jvm.<String> support(NAME).add(17, "4.39");
+	private static final Jvm.Support<String> JVM_SUPPORT = Jvm.<String> support(NAME).add(17, "4.40");
 
 	public static String defaultVersion() {
 		return JVM_SUPPORT.getRecommendedFormatterVersion();
@@ -76,6 +76,11 @@ protected P2Model model(String version) {
 			return model;
 		}
 
+		@Override
+		protected String lockfileResourcePath(String version) {
+			return "/com/diffplug/spotless/extra/eclipse_jdt_formatter/v" + version + ".lockfile";
+		}
+
 		@Override
 		public void setVersion(String version) {
 			if (version.endsWith(".0")) {

lib-extra/src/main/resources/com/diffplug/spotless/extra/eclipse_jdt_formatter/v4.11.lockfile

@@ -0,0 +1,2 @@
+# Spotless formatter based on Eclipse-JDT 4.11
+org.eclipse.jdt:org.eclipse.jdt.core:3.17.0

lib-extra/src/main/resources/com/diffplug/spotless/extra/eclipse_jdt_formatter/v4.39.lockfile

@@ -0,0 +1,2 @@
+# Spotless formatter based on Eclipse-JDT 4.39
+org.eclipse.jdt:org.eclipse.jdt.core:3.45.0

lib-extra/src/main/resources/com/diffplug/spotless/extra/eclipse_jdt_formatter/v4.40.lockfile

@@ -0,0 +1,2 @@
+# Spotless formatter based on Eclipse-JDT 4.40
+org.eclipse.jdt:org.eclipse.jdt.core:3.46.0

lib-extra/src/main/resources/com/diffplug/spotless/extra/eclipse_jdt_formatter/v4.9.lockfile

@@ -0,0 +1,2 @@
+# Spotless formatter based on Eclipse-JDT 4.9
+org.eclipse.jdt:org.eclipse.jdt.core:3.15.0

lib-extra/src/test/java/com/diffplug/spotless/extra/EquoBasedStepBuilderLockfileTest.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2016-2026 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.extra;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.diffplug.common.collect.ImmutableMap;
+import com.diffplug.spotless.StepHarness;
+import com.diffplug.spotless.Provisioner;
+
+import dev.equo.solstice.p2.P2Model;
+
+class EquoBasedStepBuilderLockfileTest {
+
+	@Test
+	void missingEmbeddedLockfileFallsBackToP2() throws Exception {
+		P2Provisioner p2Provisioner = mock();
+		Provisioner mavenProvisioner = mock();
+		when(p2Provisioner.provisionP2Dependencies(any(), any(), any())).thenReturn(List.of());
+		EquoBasedStepBuilder builder = builderWithLockfilePath("/com/diffplug/spotless/extra/missing.lockfile", p2Provisioner, mavenProvisioner);
+		StepHarness.forStep(builder.build()).test("class T {}", "class T {}");
+		verify(p2Provisioner).provisionP2Dependencies(any(), any(), any());
+		verifyNoInteractions(mavenProvisioner);
+	}
+
+	@Test
+	void lockfilePathMustBeAbsolute() {
+		P2Provisioner p2Provisioner = mock();
+		Provisioner mavenProvisioner = mock();
+		EquoBasedStepBuilder builder = builderWithLockfilePath("com/diffplug/spotless/extra/empty.lockfile",
+				p2Provisioner, mavenProvisioner);
+		IllegalArgumentException exception = assertThrows(IllegalArgumentException.class,
+				() -> StepHarness.forStep(builder.build()).test("class T {}", "class T {}"));
+		assertTrue(exception.getMessage().contains("must start with '/'"));
+		verifyNoInteractions(p2Provisioner, mavenProvisioner);
+	}
+
+	@Test
+	void emptyEmbeddedLockfileThrows() {
+		P2Provisioner p2Provisioner = mock();
+		Provisioner mavenProvisioner = mock();
+		EquoBasedStepBuilder builder = builderWithLockfilePath("/com/diffplug/spotless/extra/empty.lockfile",
+				p2Provisioner, mavenProvisioner);
+		IllegalArgumentException exception = assertThrows(IllegalArgumentException.class,
+				() -> StepHarness.forStep(builder.build()).test("class T {}", "class T {}"));
+		assertTrue(exception.getMessage().contains("No dependencies defined in lockfile"));
+		verifyNoInteractions(p2Provisioner, mavenProvisioner);
+	}
+
+	private static EquoBasedStepBuilder builderWithLockfilePath(String lockfilePath, P2Provisioner p2Provisioner, Provisioner mavenProvisioner) {
+		return new EquoBasedStepBuilder(
+				"lockfile test formatter",
+				mavenProvisioner,
+				p2Provisioner,
+				"4.40",
+				state -> input -> input,
+				ImmutableMap.builder()) {
+			@Override
+			protected P2Model model(String version) {
+				return new P2Model();
+			}
+
+			@Override
+			protected String lockfileResourcePath(String version) {
+				return lockfilePath;
+			}
+		};
+	}
+
+}

lib-extra/src/test/java/com/diffplug/spotless/extra/java/EclipseJdtFormatterStepTest.java

@@ -15,19 +15,27 @@
  */
 package com.diffplug.spotless.extra.java;
 
-import java.util.stream.Stream;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verifyNoInteractions;
+
+import java.util.List;
 
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.FieldSource;
 
+import com.diffplug.spotless.StepHarnessWithFile;
 import com.diffplug.spotless.TestP2Provisioner;
 import com.diffplug.spotless.TestProvisioner;
 import com.diffplug.spotless.extra.EquoBasedStepBuilder;
+import com.diffplug.spotless.extra.P2Provisioner;
 import com.diffplug.spotless.extra.eclipse.EquoResourceHarness;
 
 class EclipseJdtFormatterStepTest extends EquoResourceHarness {
+
+	private static final List<String> EMBEDDED_LOCKFILE_VERSIONS = List.of("4.9", "4.11", "4.39", EclipseJdtFormatterStep.defaultVersion());
+
 	private static EquoBasedStepBuilder createBuilder() {
 		return EclipseJdtFormatterStep.createBuilder(TestProvisioner.mavenCentral(), TestP2Provisioner.defaultProvisioner());
 	}
@@ -37,15 +45,24 @@ public EclipseJdtFormatterStepTest() {
 	}
 
 	@ParameterizedTest
-	@MethodSource
+	@FieldSource("EMBEDDED_LOCKFILE_VERSIONS")
 	void formatWithVersion(String version) throws Exception {
 		harnessFor(version).test("test.java",
 				"package p; class C{}",
 				"package p;\nclass C {\n}");
 	}
 
-	private static Stream<String> formatWithVersion() {
-		return Stream.of("4.9", EclipseJdtFormatterStep.defaultVersion());
+	@ParameterizedTest
+	@FieldSource("EMBEDDED_LOCKFILE_VERSIONS")
+	void embeddedLockfileVersionsDoNotUseP2(String version) {
+		P2Provisioner p2Provisioner = mock();
+		EclipseJdtFormatterStep.Builder builder = EclipseJdtFormatterStep.createBuilder(TestProvisioner.mavenCentral(), p2Provisioner);
+		builder.setVersion(version);
+		StepHarnessWithFile.forStep(this, builder.build()).test(
+				"test.java",
+				"package p; class C{}",
+				"package p;\nclass C {\n}");
+		verifyNoInteractions(p2Provisioner);
 	}
 
 	/** New format interface requires source file information to distinguish module-info from compilation unit */