Convert all logging statements from slf4j to jul

conventions/src/main/kotlin/io.opentelemetry.instrumentation.javaagent-instrumentation.gradle.kts

@@ -11,7 +11,6 @@ dependencies {
   add("muzzleBootstrap", "io.opentelemetry.javaagent:opentelemetry-javaagent-instrumentation-api")
   add("muzzleTooling", "io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api")
   add("muzzleTooling", "io.opentelemetry.javaagent:opentelemetry-javaagent-tooling")
-  add("muzzleTooling", "org.slf4j:slf4j-simple")
 
   /*
     Dependencies added to this configuration will be found by the muzzle gradle plugin during code

examples/extension/build.gradle

@@ -110,7 +110,6 @@ dependencies {
   add("muzzleBootstrap", "io.opentelemetry.javaagent:opentelemetry-javaagent-instrumentation-api:${versions.opentelemetryJavaagentAlpha}")
   add("muzzleTooling", "io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api:${versions.opentelemetryJavaagentAlpha}")
   add("muzzleTooling", "io.opentelemetry.javaagent:opentelemetry-javaagent-tooling:${versions.opentelemetryJavaagentAlpha}")
-  add("muzzleTooling", "org.slf4j:slf4j-simple:1.7.36")
 }
 
 //Produces a copy of upstream javaagent with this extension jar included inside it

instrumentation/jetty-httpclient/jetty-httpclient-9.2/library/src/main/java/io/opentelemetry/instrumentation/jetty/httpclient/v9_2/internal/JettyClientHttpAttributesGetter.java

@@ -113,10 +113,12 @@ private static Long getLongFromJettyHttpField(HttpField httpField) {
     try {
       longFromField = httpField != null ? Long.getLong(httpField.getValue()) : null;
     } catch (NumberFormatException t) {
-      logger.log(
-          FINE,
-          "Value {0} is not valid number format for header field: {1}",
-          new String[] {httpField.getValue(), httpField.getName()});
+      if (logger.isLoggable(FINE)) {
+        logger.log(
+            FINE,
+            "Value {0} is not valid number format for header field: {1}",
+            new Object[] {httpField.getValue(), httpField.getName()});
+      }
     }
     return longFromField;
   }

instrumentation/micrometer/micrometer-1.5/library/src/main/java/io/opentelemetry/instrumentation/micrometer/v1_5/TimeUnitHelper.java

@@ -45,10 +45,12 @@ static TimeUnit parseConfigValue(@Nullable String value, TimeUnit defaultUnit) {
       case "days":
         return TimeUnit.DAYS;
       default:
-        logger.log(
-            WARNING,
-            "Invalid base time unit: '{0}'; using '{1}' as the base time unit instead",
-            new String[] {value, getUnitString(defaultUnit)});
+        if (logger.isLoggable(WARNING)) {
+          logger.log(
+              WARNING,
+              "Invalid base time unit: '{0}'; using '{1}' as the base time unit instead",
+              new Object[] {value, getUnitString(defaultUnit)});
+        }
         return defaultUnit;
     }
   }

javaagent-bootstrap/build.gradle.kts

@@ -8,6 +8,7 @@ group = "io.opentelemetry.javaagent"
 dependencies {
   implementation(project(":instrumentation-api"))
   implementation("org.slf4j:slf4j-api")
+  implementation("org.slf4j:slf4j-simple")
 
   testImplementation(project(":testing-common"))
 }

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

@@ -5,12 +5,24 @@
 
 package io.opentelemetry.javaagent.bootstrap;
 
+import static java.util.logging.Level.FINE;
+
+import java.util.logging.Logger;
+
 /**
  * Class used for exception handler logging.
  *
  * <p>See io.opentelemetry.javaagent.tooling.ExceptionHandlers
  */
 public final class ExceptionLogger {
 
+  private static final Logger logger = Logger.getLogger(ExceptionLogger.class.getName());
+
+  /** See {@code io.opentelemetry.javaagent.tooling.ExceptionHandlers} for usages. */
+  @SuppressWarnings("unused")
+  public static void logSuppressedError(String message, Throwable error) {
+    logger.log(FINE, message, error);
+  }
+
   private ExceptionLogger() {}
 }

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

@@ -55,12 +55,14 @@ static TypeDescription safeAsErasure(TypeDefinition typeDefinition) {
     try {
       return typeDefinition.asErasure();
     } catch (Throwable e) {
-      logger.log(
-          FINE,
-          "{0} trying to get erasure for target {1}: {2}",
-          new String[] {
-            e.getClass().getSimpleName(), safeTypeDefinitionName(typeDefinition), e.getMessage()
-          });
+      if (logger.isLoggable(FINE)) {
+        logger.log(
+            FINE,
+            "{0} trying to get erasure for target {1}: {2}",
+            new Object[] {
+              e.getClass().getSimpleName(), safeTypeDefinitionName(typeDefinition), e.getMessage()
+            });
+      }
       return null;
     }
   }

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

@@ -102,12 +102,14 @@ static TypeDefinition safeGetSuperClass(TypeDefinition typeDefinition) {
     try {
       return typeDefinition.getSuperClass();
     } catch (Throwable e) {
-      logger.log(
-          FINE,
-          "{0} trying to get super class for target {1}: {2}",
-          new String[] {
-            e.getClass().getSimpleName(), safeTypeDefinitionName(typeDefinition), e.getMessage()
-          });
+      if (logger.isLoggable(FINE)) {
+        logger.log(
+            FINE,
+            "{0} trying to get super class for target {1}: {2}",
+            new Object[] {
+              e.getClass().getSimpleName(), safeTypeDefinitionName(typeDefinition), e.getMessage()
+            });
+      }
       return null;
     }
   }
@@ -191,12 +193,14 @@ public Iterator<TypeDefinition> iterator() {
     }
 
     private static void logException(TypeDefinition typeDefinition, Throwable e) {
-      logger.log(
-          FINE,
-          "{0} trying to get interfaces for target {1}: {2}",
-          new String[] {
-            e.getClass().getSimpleName(), safeTypeDefinitionName(typeDefinition), e.getMessage()
-          });
+      if (logger.isLoggable(FINE)) {
+        logger.log(
+            FINE,
+            "{0} trying to get interfaces for target {1}: {2}",
+            new Object[] {
+              e.getClass().getSimpleName(), safeTypeDefinitionName(typeDefinition), e.getMessage()
+            });
+      }
     }
   }
 }

javaagent-instrumentation-api/src/main/java/io/opentelemetry/javaagent/instrumentation/api/concurrent/PropagatedContext.java

@@ -29,7 +29,7 @@ void setContext(Context context) {
     boolean result = contextUpdater.compareAndSet(this, null, context);
     if (!result) {
       Context currentPropagatedContext = contextUpdater.get(this);
-      if (currentPropagatedContext != context) {
+      if (currentPropagatedContext != context && logger.isLoggable(FINE)) {
         logger.log(
             FINE,
             "Failed to propagate context because previous propagated context is already set; new: {0}, old: {1}",

javaagent-tooling/build.gradle.kts

@@ -50,7 +50,6 @@ dependencies {
   implementation("io.opentelemetry:opentelemetry-sdk-extension-jaeger-remote-sampler")
 
   api("net.bytebuddy:byte-buddy-dep")
-  implementation("org.slf4j:slf4j-api")
 
   annotationProcessor("com.google.auto.service:auto-service")
   compileOnly("com.google.auto.service:auto-service-annotations")

javaagent-tooling/javaagent-tooling-java9/build.gradle.kts

@@ -9,7 +9,6 @@ dependencies {
   implementation(project(":javaagent-bootstrap"))
 
   implementation("net.bytebuddy:byte-buddy-dep")
-  implementation("org.slf4j:slf4j-api")
 
   // Used by byte-buddy but not brought in as a transitive dependency.
   compileOnly("com.google.code.findbugs:annotations")

javaagent-tooling/javaagent-tooling-java9/src/main/java/io/opentelemetry/javaagent/tooling/ExposeAgentBootstrapListener.java

@@ -5,23 +5,26 @@
 
 package io.opentelemetry.javaagent.tooling;
 
+import static java.util.logging.Level.FINE;
+
 import io.opentelemetry.javaagent.bootstrap.AgentClassLoader;
 import java.lang.instrument.Instrumentation;
 import java.util.Collections;
+import java.util.logging.Logger;
 import net.bytebuddy.agent.builder.AgentBuilder;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.dynamic.DynamicType;
 import net.bytebuddy.dynamic.loading.ClassInjector;
 import net.bytebuddy.utility.JavaModule;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Ensures that transformed classes can read agent classes in bootstrap class loader and injected
  * classes in unnamed module of their class loader.
  */
 public class ExposeAgentBootstrapListener extends AgentBuilder.Listener.Adapter {
-  private static final Logger logger = LoggerFactory.getLogger(ExposeAgentBootstrapListener.class);
+  private static final Logger logger =
+      Logger.getLogger(ExposeAgentBootstrapListener.class.getName());
+
   // unnamed module in bootstrap class loader
   private static final JavaModule agentBootstrapModule =
       JavaModule.of(AgentClassLoader.class.getModule());
@@ -52,7 +55,12 @@ private void exposeModule(JavaModule fromModule, JavaModule targetModule) {
     if (fromModule != JavaModule.UNSUPPORTED
         && fromModule.isNamed()
         && !fromModule.canRead(targetModule)) {
-      logger.debug("Adding module read from {} to {}", fromModule, targetModule);
+
+      if (logger.isLoggable(FINE)) {
+        logger.log(
+            FINE, "Adding module read from {0} to {1}", new Object[] {fromModule, targetModule});
+      }
+
       ClassInjector.UsingInstrumentation.redefineModule(
           instrumentation,
           fromModule,

javaagent-tooling/javaagent-tooling-java9/src/main/java/io/opentelemetry/javaagent/tooling/UnsafeInitializer.java

@@ -5,17 +5,18 @@
 
 package io.opentelemetry.javaagent.tooling;
 
+import static java.util.logging.Level.WARNING;
+
 import io.opentelemetry.javaagent.bootstrap.AgentClassLoader;
 import java.lang.instrument.Instrumentation;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import java.util.logging.Logger;
 
 public class UnsafeInitializer {
-  private static final Logger logger = LoggerFactory.getLogger(UnsafeInitializer.class);
+  private static final Logger logger = Logger.getLogger(UnsafeInitializer.class.getName());
 
   static void initialize(Instrumentation instrumentation, ClassLoader classLoader) {
     initialize(instrumentation, classLoader, true);
@@ -56,7 +57,7 @@ private static void initialize(
     try {
       SunMiscUnsafeGenerator.generateUnsafe(unsafeClass, (AgentClassLoader) classLoader);
     } catch (Throwable throwable) {
-      logger.warn("Unsafe generation failed", throwable);
+      logger.log(WARNING, "Unsafe generation failed", throwable);
     }
   }