Avoid unsafe string encoder on Android

exporters/common/src/main/java/io/opentelemetry/exporter/internal/marshal/StringEncoderHolder.java

@@ -39,6 +39,12 @@ public static StringEncoder createFallbackEncoder() {
    */
   @Nullable
   public static StringEncoder createUnsafeEncoder() {
+    // Android exposes sun.misc.Unsafe, but String does not have the OpenJDK internal fields used by
+    // UnsafeStringEncoder. ART logs an error when these missing fields are queried, even though the
+    // exception is caught.
+    if ("Dalvik".equals(System.getProperty("java.vm.name"))) {
+      return null;
+    }
     return UnsafeStringEncoder.createIfAvailable();
   }
 

exporters/common/src/test/java/io/opentelemetry/exporter/internal/marshal/StringEncoderTest.java

@@ -13,6 +13,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.DisabledOnJre;
 import org.junit.jupiter.api.condition.JRE;
+import org.junitpioneer.jupiter.SetSystemProperty;
 
 class StringEncoderTest {
 
@@ -57,6 +58,12 @@ void testUtf8SizeLatin1_VarHandle() {
     testUtf8SizeLatin1(varHandleStringEncoder);
   }
 
+  @Test
+  @SetSystemProperty(key = "java.vm.name", value = "Dalvik")
+  void unsafeStringEncoderNotAvailableOnAndroid() {
+    assertThat(StringEncoderHolder.createUnsafeEncoder()).isNull();
+  }
+
   @SuppressWarnings("AvoidEscapedUnicodeCharacters")
   private static void testUtf8Encoding(StringEncoder stringEncoder) {
     assertThat(stringEncoder).isNotNull();