Migrates to jdk's compilation mechanism; fixes gh-2154

Author: marcingrzejszczak

pom.xml

@@ -66,7 +66,6 @@
 		<xerces.version>2.12.2</xerces.version>
 		<jacoco-maven-plugin.version>0.8.8</jacoco-maven-plugin.version>
 		<exec-maven-plugin.version>1.6.0</exec-maven-plugin.version>
-		<InMemoryJavaCompiler.version>1.3.0</InMemoryJavaCompiler.version>
 
 		<contract.kotlin.version>1.8.22</contract.kotlin.version>
 		<commons-beanutils.version>1.9.4</commons-beanutils.version>

spring-cloud-contract-verifier/pom.xml

@@ -247,12 +247,6 @@
 			<artifactId>spring-boot-starter-jersey</artifactId>
 			<scope>test</scope>
 		</dependency>-->
-		<dependency>
-			<groupId>org.mdkt.compiler</groupId>
-			<artifactId>InMemoryJavaCompiler</artifactId>
-			<version>${InMemoryJavaCompiler.version}</version>
-			<scope>test</scope>
-		</dependency>
 		<dependency>
 			<artifactId>jetty-ee10-servlet</artifactId>
 			<groupId>org.eclipse.jetty.ee10</groupId>

spring-cloud-contract-verifier/src/test/groovy/org/springframework/cloud/contract/verifier/builder/MockMvcMethodBodyBuilderWithMatchersSpec.groovy

@@ -17,7 +17,6 @@
 package org.springframework.cloud.contract.verifier.builder
 
 import org.junit.Rule
-import org.mdkt.compiler.CompilationException
 import spock.lang.Issue
 import spock.lang.Shared
 import spock.lang.Specification
@@ -238,7 +237,7 @@ class MockMvcMethodBodyBuilderWithMatchersSpec extends Specification implements
 			try {
 				SyntaxChecker.tryToCompileWithoutCompileStatic(methodBuilderName, test)
 			}
-			catch (CompilationException classFormatError) {
+			catch (Exception classFormatError) {
 				String output = classFormatError.message
 				assert output.contains('cannot find symbol')
 				assert output.contains('assertThatValueIsANumber')

spring-cloud-contract-verifier/src/test/groovy/org/springframework/cloud/contract/verifier/util/SyntaxChecker.groovy

@@ -19,6 +19,16 @@ package org.springframework.cloud.contract.verifier.util
 import java.lang.reflect.Method
 
 import javax.inject.Inject
+import javax.tools.Diagnostic
+import javax.tools.DiagnosticCollector
+import javax.tools.FileObject
+import javax.tools.ForwardingJavaFileManager
+import javax.tools.JavaCompiler
+import javax.tools.JavaFileManager
+import javax.tools.JavaFileObject
+import javax.tools.SimpleJavaFileObject
+import javax.tools.StandardJavaFileManager
+import javax.tools.ToolProvider
 import javax.ws.rs.client.Entity
 import javax.ws.rs.client.WebTarget
 import javax.ws.rs.core.Response
@@ -35,7 +45,6 @@ import org.codehaus.groovy.control.customizers.ASTTransformationCustomizer
 import org.codehaus.groovy.control.customizers.ImportCustomizer
 import org.junit.Rule
 import org.junit.Test
-import org.mdkt.compiler.InMemoryJavaCompiler
 import org.w3c.dom.Document
 import org.xml.sax.InputSource
 
@@ -46,6 +55,7 @@ import org.springframework.cloud.contract.verifier.messaging.internal.ContractVe
 import org.springframework.cloud.contract.verifier.messaging.internal.ContractVerifierObjectMapper
 import org.springframework.cloud.contract.verifier.messaging.util.ContractVerifierMessagingUtil
 import org.springframework.util.ReflectionUtils
+
 /**
  * checking the syntax of produced scripts
  */
@@ -110,8 +120,7 @@ private void test(String test) {
 		try {
 			if (builderName.toLowerCase().contains("spock")) {
 				tryToCompileGroovy(builderName, test)
-			}
-			else {
+			} else {
 				tryToCompileJava(builderName, test)
 			}
 		} catch (Throwable t) {
@@ -125,8 +134,7 @@ private void test(String test) {
 			if (builderName.toLowerCase().contains("spock")) {
 				Script script = tryToCompileGroovy(builderName, test)
 				script.invokeMethod("validate_method()", null)
-			}
-			else {
+			} else {
 				Class clazz = tryToCompileJava(builderName, test)
 				Method method = ReflectionUtils.findMethod(clazz, "validate_method")
 				method.invoke(clazz.newInstance())
@@ -141,8 +149,7 @@ private void test(String test) {
 	static void tryToCompileWithoutCompileStatic(String builderName, String test) {
 		if (builderName.toLowerCase().contains("spock")) {
 			tryToCompileGroovy(builderName, test, false)
-		}
-		else {
+		} else {
 			tryToCompileJava(builderName, test)
 		}
 	}
@@ -162,7 +169,7 @@ private void test(String test) {
 
 	private static String updatedTest(String test, String className) {
 		test.replaceAll("class FooTest", "class " + className)
-			.replaceAll("import javax.ws.rs.core.Response", "import javax.ws.rs.core.Response; import javax.ws.rs.client.WebTarget;")
+				.replaceAll("import javax.ws.rs.core.Response", "import javax.ws.rs.core.Response; import javax.ws.rs.client.WebTarget;")
 	}
 
 	private static GString getStaticImports(String builderName) {
@@ -176,15 +183,43 @@ private void test(String test) {
 		String className = className(test)
 		String fqnClassName = "com.example.${className}"
 		test = test.replaceAll("class FooTest", "class " + className)
-		.replaceAll("import javax.ws.rs.core.Response", "import javax.ws.rs.core.Response; import javax.ws.rs.client.WebTarget;")
+				.replaceAll("import javax.ws.rs.core.Response", "import javax.ws.rs.core.Response; import javax.ws.rs.client.WebTarget;")
 		return compileJava(fqnClassName, test)
 
 	}
 
-	private static Class<?> compileJava(String fqnClassName, String test) {
-		return InMemoryJavaCompiler.newInstance()
-							.ignoreWarnings()
-							.compile(fqnClassName, test)
+	@CompileStatic
+	private static Class<?> compileJava(String fqnClassName, String sourceCode) {
+		JavaCompiler compiler = ToolProvider.getSystemJavaCompiler()
+		DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>()
+		InMemoryClassLoader classLoader = new InMemoryClassLoader()
+		StandardJavaFileManager standardFileManager = compiler.getStandardFileManager(diagnostics, null, null)
+		JavaFileManager fileManager = new InMemoryFileManager(standardFileManager, classLoader)
+		JavaFileObject javaFile = new InMemorySourceFile(fqnClassName, sourceCode)
+		JavaCompiler.CompilationTask task = compiler.getTask(
+				new StringWriter(),
+				fileManager,
+				diagnostics,
+				null,
+				null,
+				Collections.singletonList(javaFile)
+		)
+
+		boolean success = task.call()
+		if (!success) {
+			StringBuilder errorMsg = new StringBuilder("Compilation failed:")
+			for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics.getDiagnostics()) {
+				errorMsg.append("\nLine ").append(diagnostic.getLineNumber())
+						.append(": ").append(diagnostic.getMessage(null))
+			}
+			throw new IllegalStateException(errorMsg.toString())
+		}
+
+		try {
+			return classLoader.loadClass(fqnClassName)
+		} catch (ClassNotFoundException e) {
+			throw new IllegalStateException("Failed to load compiled class", e)
+		}
 	}
 
 	private static String className(String test) {
@@ -210,4 +245,81 @@ private void test(String test) {
 		return true
 	}
 
+	@CompileStatic
+	private static class InMemorySourceFile extends SimpleJavaFileObject {
+		private final String sourceCode
+
+		InMemorySourceFile(String className, String sourceCode) {
+			super(URI.create("string:///" + className.replace('.', '/') + Kind.SOURCE.extension),
+					Kind.SOURCE)
+			this.sourceCode = sourceCode
+		}
+
+		@Override
+		CharSequence getCharContent(boolean ignoreEncodingErrors) {
+			return sourceCode
+		}
+	}
+
+	@CompileStatic
+	private static class InMemoryClassLoader extends ClassLoader {
+		private final Map<String, byte[]> classData = new HashMap<>()
+
+		void addClass(String name, byte[] data) {
+			classData.put(name, data)
+		}
+
+		@Override
+		protected Class<?> findClass(String name) throws ClassNotFoundException {
+			byte[] data = classData.get(name)
+			if (data == null) {
+				throw new ClassNotFoundException(name)
+			}
+			return defineClass(name, data, 0, data.length)
+		}
+	}
+
+	@CompileStatic
+	private static class InMemoryFileManager extends ForwardingJavaFileManager<StandardJavaFileManager> {
+		private final InMemoryClassLoader classLoader
+
+		InMemoryFileManager(StandardJavaFileManager fileManager, InMemoryClassLoader classLoader) {
+			super(fileManager)
+			this.classLoader = classLoader
+		}
+
+		@Override
+		JavaFileObject getJavaFileForOutput(Location location,
+											String className,
+											JavaFileObject.Kind kind,
+											FileObject sibling) {
+			return new InMemoryClassFile(className, classLoader)
+		}
+	}
+
+	@CompileStatic
+	private static class InMemoryClassFile extends SimpleJavaFileObject {
+		private final String className
+		private final InMemoryClassLoader classLoader
+		private final ByteArrayOutputStream outputStream = new ByteArrayOutputStream()
+
+		InMemoryClassFile(String className, InMemoryClassLoader classLoader) {
+			super(URI.create("byte:///" + className.replace('.', '/') + Kind.CLASS.extension),
+					Kind.CLASS)
+			this.className = className
+			this.classLoader = classLoader
+		}
+
+		@Override
+		OutputStream openOutputStream() {
+			outputStream.reset()
+			return new FilterOutputStream(outputStream) {
+				@Override
+				void close() throws IOException {
+					super.close()
+					classLoader.addClass(className, outputStream.toByteArray())
+				}
+			}
+		}
+	}
 }