Update to Errorprone 2.7 (#3181)

* Update to errorprone 2.7

* ToString

* Finish

benchmark-e2e/src/main/java/io/opentelemetry/e2ebenchmark/E2EAgentBenchmark.java

@@ -111,19 +111,18 @@ public class E2EAgentBenchmark {
   }
 
   static void printContainerMapping(GenericContainer<?> container) {
-    System.out.println(
-        String.format(
-            "Container %s ports exposed at %s",
-            container.getDockerImageName(),
-            container.getExposedPorts().stream()
-                .map(
-                    port ->
-                        new AbstractMap.SimpleImmutableEntry<>(
-                            port,
-                            "http://"
-                                + container.getContainerIpAddress()
-                                + ":"
-                                + container.getMappedPort(port)))
-                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))));
+    LOG.info(
+        "Container {} ports exposed at {}",
+        container.getDockerImageName(),
+        container.getExposedPorts().stream()
+            .map(
+                port ->
+                    new AbstractMap.SimpleImmutableEntry<>(
+                        port,
+                        "http://"
+                            + container.getContainerIpAddress()
+                            + ":"
+                            + container.getMappedPort(port)))
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue)));
   }
 }

build.gradle

@@ -86,6 +86,7 @@ allprojects {
         // Require Guava
         disable("AutoValueImmutableFields")
         disable("StringSplitter")
+        disable("ImmutableMemberCollection")
 
         // Don't currently use this (to indicate a local variable that's mutated) but could
         // consider for future.
@@ -107,6 +108,7 @@ allprojects {
 
         // We end up using obsolete types if a library we're instrumenting uses them.
         disable("JdkObsolete")
+        disable("JavaUtilDate")
 
         // Limits API possibilities
         disable("NoFunctionalReturnType")
@@ -128,8 +130,13 @@ allprojects {
         disable("InconsistentOverloads")
         disable("TypeParameterNaming")
 
+        // We don't use tools that recognize.
+        disable("InlineMeSuggester")
+        disable("DoNotCallSuggester")
+
         if (name.contains("Jmh") || name.contains("Test")) {
-          disable("FieldMissingNullable")
+          disable("HashCodeToString")
+          disable("MemberName")
         }
       }
     }

dependencyManagement/dependencyManagement.gradle.kts

@@ -43,7 +43,7 @@ val DEPENDENCY_SETS = listOf(
   ),
   DependencySet(
     "com.google.errorprone",
-    "2.4.0",
+    "2.7.1",
     listOf("error_prone_annotations", "error_prone_core")
   ),
   DependencySet(

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/tracer/async/Jdk8AsyncSpanEndStrategy.java

@@ -48,8 +48,8 @@ enum Jdk8AsyncSpanEndStrategy implements AsyncSpanEndStrategy {
       // so that it can be recorded to the span
       try {
         future.join();
-      } catch (Exception exception) {
-        tracer.endExceptionally(context, exception);
+      } catch (Throwable t) {
+        tracer.endExceptionally(context, t);
         return true;
       }
     }

instrumentation/executors/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/javaconcurrent/JavaExecutorInstrumentation.java

@@ -20,6 +20,7 @@ import io.opentelemetry.javaagent.instrumentation.api.concurrent.RunnableWrapper
 import io.opentelemetry.javaagent.instrumentation.api.concurrent.State;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ForkJoinTask;
 import java.util.concurrent.Future;
@@ -185,7 +186,7 @@ public class JavaExecutorInstrumentation extends AbstractExecutorInstrumentation
         tasks = wrappedTasks;
         return tasks;
       }
-      return null;
+      return Collections.emptyList();
     }
 
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
@@ -201,7 +202,7 @@ public class JavaExecutorInstrumentation extends AbstractExecutorInstrumentation
        any parent spans in case of an error.
        (according to ExecutorService docs and AbstractExecutorService code)
       */
-      if (null != throwable && wrappedTasks != null) {
+      if (null != throwable) {
         for (Callable<?> task : wrappedTasks) {
           if (task != null) {
             ContextStore<Callable, State> contextStore =

instrumentation/jaxrs/jaxrs-1.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/jaxrs/v1_0/JaxRsAnnotationsTracer.java

@@ -164,7 +164,6 @@ public class JaxRsAnnotationsTracer extends BaseTracer {
   }
 
   private static String buildSpanName(Path classPath, Path methodPath) {
-    String spanName;
     StringBuilder spanNameBuilder = new StringBuilder();
     boolean skipSlash = false;
     if (classPath != null) {
@@ -187,8 +186,7 @@ public class JaxRsAnnotationsTracer extends BaseTracer {
       spanNameBuilder.append(path);
     }
 
-    spanName = spanNameBuilder.toString().trim();
-    return spanName;
+    return spanNameBuilder.toString().trim();
   }
 
   @Override

instrumentation/jaxrs/jaxrs-2.0/jaxrs-2.0-common/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/jaxrs/v2_0/JaxRsAnnotationsTracer.java

@@ -196,7 +196,6 @@ public class JaxRsAnnotationsTracer extends BaseTracer {
   }
 
   private static String buildSpanName(Path classPath, Path methodPath) {
-    String spanName;
     StringBuilder spanNameBuilder = new StringBuilder();
     boolean skipSlash = false;
     if (classPath != null) {
@@ -220,9 +219,7 @@ public class JaxRsAnnotationsTracer extends BaseTracer {
       spanNameBuilder.append(path);
     }
 
-    spanName = spanNameBuilder.toString().trim();
-
-    return spanName;
+    return spanNameBuilder.toString().trim();
   }
 
   @Override

instrumentation/jdbc/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/jdbc/JdbcConnectionUrlParser.java

@@ -144,7 +144,6 @@ public enum JdbcConnectionUrlParser {
 
     @Override
     DbInfo.Builder doParse(String jdbcUrl, DbInfo.Builder builder) {
-      String type;
       String serverName = "";
       Integer port = null;
       String name = null;
@@ -155,7 +154,7 @@ public enum JdbcConnectionUrlParser {
         return builder;
       }
 
-      type = jdbcUrl.substring(0, hostIndex);
+      String type = jdbcUrl.substring(0, hostIndex);
 
       String[] split;
       if (type.equals("db2") || type.equals("as400")) {
@@ -845,7 +844,7 @@ public enum JdbcConnectionUrlParser {
         return withUrl(typeParsers.get(type).doParse(jdbcUrl, parsedProps), type);
       }
       return withUrl(GENERIC_URL_LIKE.doParse(jdbcUrl, parsedProps), type);
-    } catch (Exception e) {
+    } catch (RuntimeException e) {
       log.debug("Error parsing URL", e);
       return parsedProps.build();
     }

instrumentation/kafka-clients-0.11/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/kafkaclients/TracingIterator.java

@@ -47,13 +47,9 @@ public class TracingIterator implements Iterator<ConsumerRecord<?, ?>> {
 
     ConsumerRecord<?, ?> next = delegateIterator.next();
 
-    try {
-      if (next != null) {
-        currentContext = tracer.startSpan(next);
-        currentScope = currentContext.makeCurrent();
-      }
-    } catch (Exception e) {
-      log.debug("Error during decoration", e);
+    if (next != null) {
+      currentContext = tracer.startSpan(next);
+      currentScope = currentContext.makeCurrent();
     }
     return next;
   }

instrumentation/netty/netty-3.8/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v3_8/ChannelTraceContext.java

@@ -10,6 +10,7 @@ import io.opentelemetry.javaagent.instrumentation.api.ContextStore;
 import java.util.Objects;
 
 public class ChannelTraceContext {
+
   public static class Factory implements ContextStore.Factory<ChannelTraceContext> {
     public static final Factory INSTANCE = new Factory();
 
@@ -74,4 +75,16 @@ public class ChannelTraceContext {
   public int hashCode() {
     return Objects.hash(connectionContext, clientParentContext, context);
   }
+
+  @Override
+  public String toString() {
+    return "ChannelTraceContext{"
+        + "connectionContext="
+        + connectionContext
+        + ", clientParentContext="
+        + clientParentContext
+        + ", context="
+        + context
+        + '}';
+  }
 }

instrumentation/servlet/servlet-3.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/servlet/v3_0/Servlet3FilterMappingResolverFactory.java

@@ -44,6 +44,7 @@ public class Servlet3FilterMappingResolverFactory
   }
 
   @Override
+  @SuppressWarnings("ReturnsNullCollection")
   protected Collection<String> getServletMappings(String servletName) {
     ServletRegistration servletRegistration =
         filterConfig.getServletContext().getServletRegistration(servletName);

instrumentation/servlet/servlet-3.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/servlet/v3_0/Servlet3MappingResolverFactory.java

@@ -22,6 +22,7 @@ public class Servlet3MappingResolverFactory extends ServletMappingResolverFactor
   }
 
   @Override
+  @SuppressWarnings("ReturnsNullCollection")
   public Collection<String> getMappings() {
     String servletName = servletConfig.getServletName();
     ServletContext servletContext = servletConfig.getServletContext();

instrumentation/servlet/servlet-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/servlet/v5_0/service/JakartaServletFilterMappingResolverFactory.java

@@ -44,6 +44,7 @@ public class JakartaServletFilterMappingResolverFactory
   }
 
   @Override
+  @SuppressWarnings("ReturnsNullCollection")
   protected Collection<String> getServletMappings(String servletName) {
     ServletRegistration servletRegistration =
         filterConfig.getServletContext().getServletRegistration(servletName);

instrumentation/servlet/servlet-5.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/servlet/v5_0/service/JakartaServletMappingResolverFactory.java

@@ -22,6 +22,7 @@ public class JakartaServletMappingResolverFactory extends ServletMappingResolver
   }
 
   @Override
+  @SuppressWarnings("ReturnsNullCollection")
   public Collection<String> getMappings() {
     String servletName = servletConfig.getServletName();
     ServletContext servletContext = servletConfig.getServletContext();

instrumentation/servlet/servlet-common/library/src/main/java/io/opentelemetry/instrumentation/servlet/naming/ServletFilterMappingResolverFactory.java

@@ -25,6 +25,9 @@ public abstract class ServletFilterMappingResolverFactory<FILTERREGISTRATION> {
 
   protected abstract Collection<String> getServletMappings(String servletName);
 
+  // TODO(anuraaga): We currently treat null as no mappings, and empty as having a default mapping.
+  // Error prone is correctly flagging this behavior as error prone.
+  @SuppressWarnings("ReturnsNullCollection")
   private Collection<String> getMappings() {
     FILTERREGISTRATION filterRegistration = getFilterRegistration();
     if (filterRegistration == null) {

instrumentation/spymemcached-2.12/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spymemcached/CompletionListener.java

@@ -55,9 +55,9 @@ public abstract class CompletionListener<T> {
       // Avoid swallowing InterruptedException
       tracer().endExceptionally(context, e);
       Thread.currentThread().interrupt();
-    } catch (Exception e) {
+    } catch (Throwable t) {
       // This should never happen, just in case to make sure we cover all unexpected exceptions
-      tracer().endExceptionally(context, e);
+      tracer().endExceptionally(context, t);
     } finally {
       tracer().end(context);
     }

instrumentation/vertx-reactive-3.5/javaagent/src/test/java/VertxReactiveWebServer.java

@@ -126,7 +126,6 @@ public class VertxReactiveWebServer extends AbstractVerticle {
           .rxQuery("SELECT id" + queryInfix + ", name, price, weight FROM products")
           .flatMap(
               result -> {
-                Thread.dumpStack();
                 JsonArray arr = new JsonArray();
                 result.getRows().forEach(arr::add);
                 return Single.just(arr);

instrumentation/vertx-web-3.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/vertx/RoutingContextHandlerWrapper.java

@@ -37,7 +37,7 @@ public final class RoutingContextHandlerWrapper implements Handler<RoutingContex
         // https://github.com/open-telemetry/opentelemetry-java-instrumentation/issues/465
         serverSpan.updateName(context.currentRoute().getPath());
       }
-    } catch (Exception ex) {
+    } catch (RuntimeException ex) {
       log.error("Failed to update server span name with vert.x route", ex);
     }
     try {

javaagent-bootstrap/src/main/java/io/opentelemetry/javaagent/OpenTelemetryAgent.java

@@ -42,6 +42,8 @@ import java.util.regex.Pattern;
  *   <li>Do dot touch any logging facilities here so we can configure them later
  * </ul>
  */
+// Too early for logging
+@SuppressWarnings("SystemOut")
 public final class OpenTelemetryAgent {
   private static final Class<?> thisClass = OpenTelemetryAgent.class;
 
@@ -197,7 +199,7 @@ public final class OpenTelemetryAgent {
   public static void main(String... args) {
     try {
       System.out.println(OpenTelemetryAgent.class.getPackage().getImplementationVersion());
-    } catch (Exception e) {
+    } catch (RuntimeException e) {
       System.out.println("Failed to parse agent version");
       e.printStackTrace();
     }

javaagent-extension-api/src/main/java/io/opentelemetry/javaagent/extension/matcher/LoggingFailSafeMatcher.java

@@ -50,7 +50,7 @@ class LoggingFailSafeMatcher<T> extends ElementMatcher.Junction.AbstractBase<T>
   public boolean matches(T target) {
     try {
       return matcher.matches(target);
-    } catch (Exception e) {
+    } catch (Throwable e) {
       log.debug(description, e);
       return fallback;
     }

javaagent-extension-api/src/main/java/io/opentelemetry/javaagent/extension/matcher/SafeErasureMatcher.java

@@ -53,7 +53,7 @@ class SafeErasureMatcher<T extends TypeDefinition> extends ElementMatcher.Juncti
   static TypeDescription safeAsErasure(TypeDefinition typeDefinition) {
     try {
       return typeDefinition.asErasure();
-    } catch (Exception e) {
+    } catch (Throwable e) {
       if (log.isDebugEnabled()) {
         log.debug(
             "{} trying to get erasure for target {}: {}",

javaagent-extension-api/src/main/java/io/opentelemetry/javaagent/extension/matcher/SafeHasSuperTypeMatcher.java

@@ -101,7 +101,7 @@ class SafeHasSuperTypeMatcher extends ElementMatcher.Junction.AbstractBase<TypeD
   static TypeDefinition safeGetSuperClass(TypeDefinition typeDefinition) {
     try {
       return typeDefinition.getSuperClass();
-    } catch (Exception e) {
+    } catch (Throwable e) {
       if (log.isDebugEnabled()) {
         log.debug(
             "{} trying to get super class for target {}: {}",
@@ -156,7 +156,7 @@ class SafeHasSuperTypeMatcher extends ElementMatcher.Junction.AbstractBase<TypeD
       Iterator<TypeDescription.Generic> it = null;
       try {
         it = typeDefinition.getInterfaces().iterator();
-      } catch (Exception e) {
+      } catch (Throwable e) {
         logException(typeDefinition, e);
       }
       this.it = it;
@@ -168,7 +168,7 @@ class SafeHasSuperTypeMatcher extends ElementMatcher.Junction.AbstractBase<TypeD
         try {
           next = it.next();
           return true;
-        } catch (Exception e) {
+        } catch (Throwable e) {
           logException(typeDefinition, e);
           return false;
         }
@@ -191,7 +191,7 @@ class SafeHasSuperTypeMatcher extends ElementMatcher.Junction.AbstractBase<TypeD
       return this;
     }
 
-    private static void logException(TypeDefinition typeDefinition, Exception e) {
+    private static void logException(TypeDefinition typeDefinition, Throwable e) {
       if (log.isDebugEnabled()) {
         log.debug(
             "{} trying to get interfaces for target {}: {}",

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/AgentInstaller.java

@@ -421,7 +421,7 @@ public class AgentInstaller {
       for (ComponentInstaller componentInstaller : componentInstallers) {
         try {
           componentInstaller.afterByteBuddyAgent(config);
-        } catch (Exception e) {
+        } catch (RuntimeException e) {
           log.error("Failed to execute {}", componentInstaller.getClass().getName(), e);
         }
       }

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/ExtensionClassLoader.java

@@ -19,7 +19,7 @@ import java.net.URLClassLoader;
 // TODO find a way to initialize logging before using this class
 // TODO support scanning a folder for several extension jars and keep them isolated from each other
 // Used by AgentInitializer
-@SuppressWarnings("unused")
+@SuppressWarnings({"unused", "SystemOut"})
 public class ExtensionClassLoader extends URLClassLoader {
   // NOTE it's important not to use slf4j in this class, because this class is used before slf4j is
   // configured, and so using slf4j here would initialize slf4j-simple before we have a chance to

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/bytebuddy/AgentCachingPoolStrategy.java

@@ -199,6 +199,19 @@ public class AgentCachingPoolStrategy implements AgentBuilder.PoolStrategy {
     public final int hashCode() {
       return hashCode;
     }
+
+    @Override
+    public String toString() {
+      return "TypeCacheKey{"
+          + "loaderHash="
+          + loaderHash
+          + ", loaderRef="
+          + loaderRef
+          + ", className='"
+          + className
+          + '\''
+          + '}';
+    }
   }
 
   static final class SharedResolutionCacheAdapter implements TypePool.CacheProvider {

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/bytebuddy/ExceptionHandlers.java

@@ -27,7 +27,7 @@ public final class ExceptionHandlers {
       new ExceptionHandler.Simple(
           new StackManipulation() {
             // Pops one Throwable off the stack. Maxes the stack to at least 3.
-            private final Size size = new StackManipulation.Size(-1, 3);
+            private final StackManipulation.Size size = new StackManipulation.Size(-1, 3);
 
             @Override
             public boolean isValid() {
@@ -35,7 +35,7 @@ public final class ExceptionHandlers {
             }
 
             @Override
-            public Size apply(MethodVisitor mv, Implementation.Context context) {
+            public StackManipulation.Size apply(MethodVisitor mv, Implementation.Context context) {
               String name = context.getInstrumentedType().getName();
               ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
 

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/HelperReferenceWrapper.java

@@ -89,6 +89,23 @@ interface HelperReferenceWrapper {
     public int hashCode() {
       return Objects.hash(name, descriptor);
     }
+
+    @Override
+    public String toString() {
+      return "Method{"
+          + "isAbstract="
+          + isAbstract
+          + ", declaringClass='"
+          + declaringClass
+          + '\''
+          + ", name='"
+          + name
+          + '\''
+          + ", descriptor='"
+          + descriptor
+          + '\''
+          + '}';
+    }
   }
 
   final class Field {
@@ -124,6 +141,11 @@ interface HelperReferenceWrapper {
     public int hashCode() {
       return Objects.hash(name, descriptor);
     }
+
+    @Override
+    public String toString() {
+      return "Field{" + "name='" + name + '\'' + ", descriptor='" + descriptor + '\'' + '}';
+    }
   }
 
   class Factory {

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/MuzzleGradlePluginUtil.java

@@ -22,6 +22,8 @@ import java.util.ServiceLoader;
 import net.bytebuddy.dynamic.ClassFileLocator;
 
 /** Entry point for the muzzle gradle plugin. */
+// Runs in special classloader so tedious to provide access to the Gradle logger.
+@SuppressWarnings("SystemOut")
 public final class MuzzleGradlePluginUtil {
   private static final String INDENT = "  ";
 
@@ -101,7 +103,7 @@ public final class MuzzleGradlePluginUtil {
                     createHelperMap(allHelperClasses, agentClassLoader))
                 .transform(null, null, userClassLoader, null);
           }
-        } catch (Exception e) {
+        } catch (RuntimeException e) {
           System.err.println(
               "FAILED HELPER INJECTION. Are Helpers being injected in the correct order?");
           throw e;
@@ -140,7 +142,7 @@ public final class MuzzleGradlePluginUtil {
         for (ClassRef ref : instrumentationModule.getMuzzleReferences().values()) {
           System.out.print(prettyPrint(ref));
         }
-      } catch (Exception e) {
+      } catch (RuntimeException e) {
         String message =
             "Unexpected exception printing references for "
                 + instrumentationModule.getClass().getName();

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/ReferenceMatcher.java

@@ -17,7 +17,6 @@ import io.opentelemetry.javaagent.extension.muzzle.MethodRef;
 import io.opentelemetry.javaagent.tooling.AgentTooling;
 import io.opentelemetry.javaagent.tooling.Utils;
 import io.opentelemetry.javaagent.tooling.muzzle.InstrumentationClassPredicate;
-import io.opentelemetry.javaagent.tooling.muzzle.matcher.HelperReferenceWrapper.Method;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
@@ -121,7 +120,7 @@ public final class ReferenceMatcher {
         }
         return checkThirdPartyTypeMatch(reference, resolution.resolve());
       }
-    } catch (Exception e) {
+    } catch (RuntimeException e) {
       if (e.getMessage().startsWith("Cannot resolve type description for ")) {
         // bytebuddy throws an illegal state exception with this message if it cannot resolve types
         // TODO: handle missing type resolutions without catching bytebuddy's exceptions
@@ -188,7 +187,9 @@ public final class ReferenceMatcher {
   }
 
   private static void collectMethodsFromTypeHierarchy(
-      HelperReferenceWrapper type, Set<Method> abstractMethods, Set<Method> plainMethods) {
+      HelperReferenceWrapper type,
+      Set<HelperReferenceWrapper.Method> abstractMethods,
+      Set<HelperReferenceWrapper.Method> plainMethods) {
 
     type.getMethods()
         .forEach(method -> (method.isAbstract() ? abstractMethods : plainMethods).add(method));

javaagent/src/test/java/io/opentelemetry/javaagent/IntegrationTestUtils.java

@@ -251,7 +251,7 @@ public class IntegrationTestUtils {
         String line = null;
         while ((line = reader.readLine()) != null) {
           if (print) {
-            System.out.println(type + "> " + line);
+            logger.info("{}> {}", type, line);
           }
         }
       } catch (IOException e) {

load-generator/src/main/java/io/opentelemetry/loadgenerator/LoadGenerator.java

@@ -22,6 +22,7 @@ import picocli.CommandLine.Option;
 @Command(
     mixinStandardHelpOptions = true,
     description = "Generates traces and spans at a specified rate")
+@SuppressWarnings("SystemOut")
 public class LoadGenerator implements Callable<Integer> {
 
   private static final Tracer tracer = GlobalOpenTelemetry.getTracer("test");

smoke-tests/src/test/java/io/opentelemetry/smoketest/windows/WindowsTestContainerManager.java

@@ -230,7 +230,7 @@ public class WindowsTestContainerManager extends AbstractTestContainerManager {
     try {
       client.inspectImageCmd(imageName).exec();
       return true;
-    } catch (Exception e) {
+    } catch (RuntimeException e) {
       return false;
     }
   }

testing-common/integration-tests/src/test/groovy/AgentTestRunnerTest.groovy

@@ -119,7 +119,7 @@ class AgentTestRunnerTest extends AgentInstrumentationSpecification {
     if (!(testClassLoader instanceof URLClassLoader)) {
       // java9's system loader does not extend URLClassLoader
       // which breaks Guava ClassPath lookup
-      testClassLoader = ClasspathUtils.buildJavaClassPathClassLoader()
+      testClassLoader = buildJavaClassPathClassLoader()
     }
     try {
       return ClassPath.from(testClassLoader)
@@ -127,4 +127,27 @@ class AgentTestRunnerTest extends AgentInstrumentationSpecification {
       throw new IllegalStateException(e)
     }
   }
+
+  /**
+   * Parse JVM classpath and return ClassLoader containing all classpath entries. Inspired by Guava.
+   */
+  private static ClassLoader buildJavaClassPathClassLoader() {
+    List<URL> urls = new ArrayList<>()
+    for (String entry : getClasspath()) {
+      try {
+        try {
+          urls.add(new File(entry).toURI().toURL())
+        } catch (SecurityException e) { // File.toURI checks to see if the file is a directory
+          urls.add(new URL("file", null, new File(entry).getAbsolutePath()))
+        }
+      } catch (MalformedURLException e) {
+        throw new IllegalStateException(e)
+      }
+    }
+    return new URLClassLoader(urls.toArray(new URL[0]), (ClassLoader) null)
+  }
+
+  private static String[] getClasspath() {
+    return System.getProperty("java.class.path").split(System.getProperty("path.separator"))
+  }
 }

testing-common/src/main/java/io/opentelemetry/instrumentation/test/utils/ClasspathUtils.java

@@ -11,11 +11,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.reflect.Method;
-import java.net.MalformedURLException;
 import java.net.URL;
-import java.net.URLClassLoader;
-import java.util.ArrayList;
-import java.util.List;
 import java.util.UUID;
 import java.util.jar.JarEntry;
 import java.util.jar.JarOutputStream;
@@ -108,30 +104,6 @@ public final class ClasspathUtils {
     jarOutputStream.closeEntry();
   }
 
-  /**
-   * Parse JVM classpath and return ClassLoader containing all classpath entries. Inspired by Guava.
-   */
-  public static ClassLoader buildJavaClassPathClassLoader() {
-    List<URL> urls = new ArrayList<>();
-    for (String entry : getClasspath()) {
-      try {
-        try {
-          urls.add(new File(entry).toURI().toURL());
-        } catch (SecurityException e) { // File.toURI checks to see if the file is a directory
-          urls.add(new URL("file", null, new File(entry).getAbsolutePath()));
-        }
-      } catch (MalformedURLException e) {
-        System.err.printf(
-            "Error injecting bootstrap jar: Malformed classpath entry: %s. %s%n", entry, e);
-      }
-    }
-    return new URLClassLoader(urls.toArray(new URL[0]), null);
-  }
-
-  private static String[] getClasspath() {
-    return System.getProperty("java.class.path").split(System.getProperty("path.separator"));
-  }
-
   // Moved this to a java class because groovy was adding a hard ref to classLoader
   public static boolean isClassLoaded(String className, ClassLoader classLoader) {
     try {