Convert internal-lambda test from groovy to java (#9611)

instrumentation/internal/internal-lambda/javaagent/src/test/groovy/LambdaInstrumentationTest.groovy

@@ -1,21 +0,0 @@
-/*
- * Copyright The OpenTelemetry Authors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import io.opentelemetry.instrumentation.test.AgentInstrumentationSpecification
-import io.opentelemetry.javaagent.bootstrap.VirtualFieldInstalledMarker
-
-class LambdaInstrumentationTest extends AgentInstrumentationSpecification {
-
-  def "test transform Runnable lambda"() {
-    setup:
-    Runnable runnable = TestLambda.makeRunnable()
-
-    expect:
-    // RunnableInstrumentation adds a VirtualField to all implementors of Runnable. If lambda class
-    // is transformed then it must have context store marker interface.
-    runnable instanceof VirtualFieldInstalledMarker
-    !VirtualFieldInstalledMarker.isAssignableFrom(Runnable)
-  }
-}

instrumentation/internal/internal-lambda/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/internal/lambda/LambdaInstrumentationTest.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.internal.lambda;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.javaagent.bootstrap.VirtualFieldInstalledMarker;
+import org.junit.jupiter.api.Test;
+
+class LambdaInstrumentationTest {
+
+  @Test
+  void testTransformRunnableLambda() {
+    Runnable runnable = TestLambda.makeRunnable();
+
+    // RunnableInstrumentation adds a VirtualField to all implementors of Runnable. If lambda class
+    // is transformed then it must have context store marker interface.
+    assertThat(runnable).isInstanceOf(VirtualFieldInstalledMarker.class);
+    assertThat(VirtualFieldInstalledMarker.class.isAssignableFrom(Runnable.class)).isFalse();
+  }
+}

instrumentation/internal/internal-lambda/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/internal/lambda/TestLambda.java

@@ -3,6 +3,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+package io.opentelemetry.javaagent.instrumentation.internal.lambda;
+
 public class TestLambda {
 
   static Runnable makeRunnable() {