perf(core): Cache class lookups and collapse double probes

Class availability is fixed for the lifetime of the process, so cache
LoadClass results to avoid repeated Class.forName lookups (and the
exceptions thrown for absent classes) when the same class is probed more
than once. Also collapse the isClassAvailable-then-loadClass double
probe in the OpenTelemetry span/scopes factories into a single
loadClass call.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: runningcode

sentry/src/main/java/io/sentry/ScopesStorageFactory.java

@@ -23,24 +23,23 @@ public final class ScopesStorageFactory {
   private static @NotNull IScopesStorage createInternal(
       final @NotNull LoadClass loadClass, final @NotNull ILogger logger) {
     if (Platform.isJvm()) {
-      if (loadClass.isClassAvailable(OTEL_SCOPES_STORAGE, logger)) {
-        Class<?> otelScopesStorageClazz = loadClass.loadClass(OTEL_SCOPES_STORAGE, logger);
-        if (otelScopesStorageClazz != null) {
-          try {
-            final @Nullable Object otelScopesStorage =
-                otelScopesStorageClazz.getDeclaredConstructor().newInstance();
-            if (otelScopesStorage instanceof IScopesStorage) {
-              return (IScopesStorage) otelScopesStorage;
-            }
-          } catch (InstantiationException e) {
-            // TODO log
-          } catch (IllegalAccessException e) {
-            // TODO log
-          } catch (InvocationTargetException e) {
-            // TODO log
-          } catch (NoSuchMethodException e) {
-            // TODO log
+      final @Nullable Class<?> otelScopesStorageClazz =
+          loadClass.loadClass(OTEL_SCOPES_STORAGE, logger);
+      if (otelScopesStorageClazz != null) {
+        try {
+          final @Nullable Object otelScopesStorage =
+              otelScopesStorageClazz.getDeclaredConstructor().newInstance();
+          if (otelScopesStorage instanceof IScopesStorage) {
+            return (IScopesStorage) otelScopesStorage;
           }
+        } catch (InstantiationException e) {
+          // TODO log
+        } catch (IllegalAccessException e) {
+          // TODO log
+        } catch (InvocationTargetException e) {
+          // TODO log
+        } catch (NoSuchMethodException e) {
+          // TODO log
         }
       }
     }

sentry/src/main/java/io/sentry/SpanFactoryFactory.java

@@ -15,24 +15,23 @@ public final class SpanFactoryFactory {
   public static @NotNull ISpanFactory create(
       final @NotNull LoadClass loadClass, final @NotNull ILogger logger) {
     if (Platform.isJvm()) {
-      if (loadClass.isClassAvailable(OTEL_SPAN_FACTORY, logger)) {
-        Class<?> otelSpanFactoryClazz = loadClass.loadClass(OTEL_SPAN_FACTORY, logger);
-        if (otelSpanFactoryClazz != null) {
-          try {
-            final @Nullable Object otelSpanFactory =
-                otelSpanFactoryClazz.getDeclaredConstructor().newInstance();
-            if (otelSpanFactory instanceof ISpanFactory) {
-              return (ISpanFactory) otelSpanFactory;
-            }
-          } catch (InstantiationException e) {
-            // TODO log
-          } catch (IllegalAccessException e) {
-            // TODO log
-          } catch (InvocationTargetException e) {
-            // TODO log
-          } catch (NoSuchMethodException e) {
-            // TODO log
+      final @Nullable Class<?> otelSpanFactoryClazz =
+          loadClass.loadClass(OTEL_SPAN_FACTORY, logger);
+      if (otelSpanFactoryClazz != null) {
+        try {
+          final @Nullable Object otelSpanFactory =
+              otelSpanFactoryClazz.getDeclaredConstructor().newInstance();
+          if (otelSpanFactory instanceof ISpanFactory) {
+            return (ISpanFactory) otelSpanFactory;
           }
+        } catch (InstantiationException e) {
+          // TODO log
+        } catch (IllegalAccessException e) {
+          // TODO log
+        } catch (InvocationTargetException e) {
+          // TODO log
+        } catch (NoSuchMethodException e) {
+          // TODO log
         }
       }
     }

sentry/src/main/java/io/sentry/util/LoadClass.java

@@ -4,13 +4,25 @@
 import io.sentry.ILogger;
 import io.sentry.SentryLevel;
 import io.sentry.SentryOptions;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /** An Adapter for making Class.forName testable */
 @Open
 public class LoadClass {
 
+  /** Sentinel cached for class names that are known to be unavailable. */
+  private static final Object NOT_AVAILABLE = new Object();
+
+  /**
+   * Whether a class is on the classpath does not change during the lifetime of the process, so
+   * results are cached to avoid repeated {@link Class#forName} lookups (and the exceptions they
+   * throw for absent classes) when the same class is probed more than once.
+   */
+  private static final Map<String, Object> CLASSES = new ConcurrentHashMap<>();
+
   /**
    * Try to load a class via reflection
    *
@@ -19,11 +31,18 @@ public class LoadClass {
    * @return a Class&lt;?&gt; if it's available, or null
    */
   public @Nullable Class<?> loadClass(final @NotNull String clazz, final @Nullable ILogger logger) {
+    final @Nullable Object cached = CLASSES.get(clazz);
+    if (cached != null) {
+      return cached == NOT_AVAILABLE ? null : (Class<?>) cached;
+    }
     try {
       // Don't initialize the class just to probe for availability; it gets initialized lazily on
       // first use. This avoids running unrelated static initializers during SDK init.
-      return Class.forName(clazz, false, LoadClass.class.getClassLoader());
+      final Class<?> loadedClass = Class.forName(clazz, false, LoadClass.class.getClassLoader());
+      CLASSES.put(clazz, loadedClass);
+      return loadedClass;
     } catch (ClassNotFoundException e) {
+      CLASSES.put(clazz, NOT_AVAILABLE);
       if (logger != null) {
         logger.log(SentryLevel.INFO, "Class not available: " + clazz);
       }