Fix HttpExporterBuilder.copy() to preserve componentLoader field

exporters/common/src/main/java/io/opentelemetry/exporter/internal/http/HttpExporterBuilder.java

@@ -204,6 +204,7 @@ public HttpExporterBuilder<T> copy() {
     copy.meterProviderSupplier = meterProviderSupplier;
     copy.internalTelemetryVersion = internalTelemetryVersion;
     copy.proxyOptions = proxyOptions;
+    copy.componentLoader = componentLoader;
     return copy;
   }
 

exporters/common/src/test/java/io/opentelemetry/exporter/internal/http/HttpExporterBuilderTest.java

@@ -91,4 +91,15 @@ void compressionString_usesServiceClassLoader() {
     builder.setCompression("none");
     assertThat(builder).extracting("compressor").isNull();
   }
+
+  @Test
+  void copy_preservesComponentLoader() {
+    ComponentLoader customComponentLoader =
+        ComponentLoader.forClassLoader(new URLClassLoader(new URL[0], null));
+    builder.setComponentLoader(customComponentLoader);
+
+    HttpExporterBuilder<Marshaler> copiedBuilder = builder.copy();
+
+    assertThat(copiedBuilder).extracting("componentLoader").isEqualTo(customComponentLoader);
+  }
 }

exporters/otlp/all/src/test/java/io/opentelemetry/exporter/otlp/http/metrics/OtlpHttpMetricExporterBuilderTest.java

@@ -29,6 +29,7 @@
 import io.opentelemetry.api.metrics.Meter;
 import io.opentelemetry.api.metrics.MeterProvider;
 import io.opentelemetry.api.trace.TracerProvider;
+import io.opentelemetry.common.ComponentLoader;
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
 import io.opentelemetry.sdk.common.export.MemoryMode;
@@ -237,4 +238,27 @@ void verifyToBuilderPreservesSettings() {
     original.close();
     copy.close();
   }
+
+  @Test
+  void toBuilderPreservesComponentLoader() {
+    // Create a custom component loader that still has access to the necessary classes
+    // but is different from the default to test preservation
+    ComponentLoader customComponentLoader =
+        ComponentLoader.forClassLoader(this.getClass().getClassLoader());
+
+    OtlpHttpMetricExporter original =
+        OtlpHttpMetricExporter.builder()
+            .setComponentLoader(customComponentLoader)
+            .setEndpoint("http://localhost:4318/v1/metrics")
+            .build();
+
+    // toBuilder() should preserve the component loader and not throw any class loader related exceptions
+    OtlpHttpMetricExporter copy = original.toBuilder().build();
+
+    // The copy should work without class loader issues
+    assertThat(copy).isNotNull();
+
+    original.close();
+    copy.close();
+  }
 }