DataDog · PerfectSlayer · Jun 5, 2026 · Jun 5, 2026 · Jun 5, 2026 · Jun 5, 2026
@@ -82,6 +82,7 @@ public final class ConfigDefaults {
       new LinkedHashSet<>(asList(DATADOG, TRACECONTEXT, BAGGAGE));
   static final Set<PropagationStyle> DEFAULT_PROPAGATION_STYLE =
       new LinkedHashSet<>(asList(PropagationStyle.DATADOG));
+  public static final boolean DEFAULT_PROPAGATION_B3_PADDING_ENABLED = true;
   static final int DEFAULT_TRACE_BAGGAGE_MAX_ITEMS = 64;
   static final int DEFAULT_TRACE_BAGGAGE_MAX_BYTES = 8192;
   static final List<String> DEFAULT_TRACE_BAGGAGE_TAG_KEYS =

@@ -115,7 +115,6 @@
 import datadog.trace.util.AgentTaskScheduler;
 import java.io.IOException;
 import java.lang.ref.WeakReference;
-import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -140,11 +139,8 @@
  */
 public class CoreTracer implements AgentTracer.TracerAPI, TracerFlare.Reporter {
   private static final Logger log = LoggerFactory.getLogger(CoreTracer.class);
-  // UINT64 max value
-  public static final BigInteger TRACE_ID_MAX =
-      BigInteger.valueOf(2).pow(64).subtract(BigInteger.ONE);
 
-  public static final CoreTracerBuilder builder() {
+  public static CoreTracerBuilder builder() {
     return new CoreTracerBuilder();
   }
 

@@ -1,5 +1,6 @@
 package datadog.trace.core.propagation;
 
+import static datadog.trace.api.config.TracerConfig.PROPAGATION_EXTRACT_LOG_HEADER_NAMES_ENABLED;
 import static datadog.trace.bootstrap.ActiveSubsystems.APPSEC_ACTIVE;
 import static datadog.trace.bootstrap.instrumentation.api.ContextVisitors.stringValuesMap;
 import static datadog.trace.core.propagation.B3HttpCodec.B3_KEY;
@@ -9,6 +10,7 @@
 import static datadog.trace.core.propagation.B3HttpCodec.SAMPLING_PRIORITY_KEY;
 import static datadog.trace.core.propagation.B3HttpCodec.SPAN_ID_KEY;
 import static datadog.trace.core.propagation.B3HttpCodec.TRACE_ID_KEY;
+import static datadog.trace.core.propagation.HttpCodecTestHelper.headers;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -25,15 +27,14 @@
 import datadog.trace.junit.utils.tabletest.PrioritySamplingConverter;
 import datadog.trace.test.util.DDJavaSpecification;
 import java.util.HashMap;
-import java.util.LinkedHashMap;
 import java.util.Map;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.converter.ConvertWith;
 import org.tabletest.junit.TableTest;
 
-@WithConfig(key = "propagation.extract.log_header_names.enabled", value = "true")
+@WithConfig(key = PROPAGATION_EXTRACT_LOG_HEADER_NAMES_ENABLED, value = "true")
 class B3HttpExtractorTest extends DDJavaSpecification {
   private static final String SOME_HEADER = "SOME_HEADER";
   private static final String SOME_TAG = "some-tag";
@@ -74,14 +75,14 @@ void extractHttpHeaders(
       String spanIdHex,
       Integer samplingPriority,
       @ConvertWith(PrioritySamplingConverter.class) byte expectedSamplingPriority) {
-    Map<String, String> headers = new HashMap<>();
-    headers.put("", "empty key");
-    headers.put(TRACE_ID_KEY.toUpperCase(), traceIdHex);
-    headers.put(SPAN_ID_KEY.toUpperCase(), spanIdHex);
-    headers.put(SOME_HEADER, SOME_VALUE);
-    if (samplingPriority != null) {
-      headers.put(SAMPLING_PRIORITY_KEY, samplingPriority.toString());
-    }
+    // spotless:off
+    Map<String, String> headers = headers(
+        "", "empty key",
+        TRACE_ID_KEY, traceIdHex,
+        SPAN_ID_KEY, spanIdHex,
+        SOME_HEADER, SOME_VALUE,
+        SAMPLING_PRIORITY_KEY, samplingPriority != null ? samplingPriority.toString() : null);
+    // spotless:on
 
     ExtractedContext context = (ExtractedContext) extractor.extract(headers, stringValuesMap());
 
@@ -107,13 +108,16 @@ void extractHttpHeadersWithB3HeaderAtTheBeginning(
       @ConvertWith(PrioritySamplingConverter.class) byte expectedSamplingPriority) {
     String traceIdHex = "1";
     String spanIdHex = "2";
-    Map<String, String> headers = new LinkedHashMap<>();
-    headers.put("", "empty key");
-    headers.put(B3_KEY, b3);
-    headers.put(TRACE_ID_KEY.toUpperCase(), traceIdHex);
-    headers.put(SPAN_ID_KEY.toUpperCase(), spanIdHex);
-    headers.put(SOME_HEADER, SOME_VALUE);
-    headers.put(SAMPLING_PRIORITY_KEY, SAMPLING_PRIORITY_ACCEPT);
+    // spotless:off
+    Map<String, String> headers = headers(
+        "", "empty key",
+        B3_KEY, b3,
+        TRACE_ID_KEY, traceIdHex,
+        SPAN_ID_KEY, spanIdHex,
+        SOME_HEADER, SOME_VALUE,
+        SAMPLING_PRIORITY_KEY, SAMPLING_PRIORITY_ACCEPT
+    );
+    // spotless:on
 
     ExtractedContext context =
         (ExtractedContext) this.extractor.extract(headers, stringValuesMap());
@@ -136,13 +140,16 @@ void extractHttpHeadersWithB3HeaderAtTheEnd(
       @ConvertWith(PrioritySamplingConverter.class) byte expectedSamplingPriority) {
     String traceIdHex = "1";
     String spanIdHex = "2";
-    Map<String, String> headers = new LinkedHashMap<>();
-    headers.put("", "empty key");
-    headers.put(TRACE_ID_KEY.toUpperCase(), traceIdHex);
-    headers.put(SPAN_ID_KEY.toUpperCase(), spanIdHex);
-    headers.put(B3_KEY, b3);
-    headers.put(SOME_HEADER, SOME_VALUE);
-    headers.put(SAMPLING_PRIORITY_KEY, SAMPLING_PRIORITY_ACCEPT);
+    // spotless:off
+    Map<String, String> headers = headers(
+        "", "empty key",
+        TRACE_ID_KEY, traceIdHex,
+        SPAN_ID_KEY, spanIdHex,
+        B3_KEY, b3,
+        SOME_HEADER, SOME_VALUE,
+        SAMPLING_PRIORITY_KEY, SAMPLING_PRIORITY_ACCEPT
+    );
+    // spotless:on
 
     TagContext context = this.extractor.extract(headers, stringValuesMap());
 
@@ -188,9 +195,12 @@ private Map<String, Object> expectedB3Tags(TagContext context) {
   })
   void extract128BitIdTruncatesIdTo64Bit(
       String traceId, String spanId, String expectedTraceIdHex, Long expectedSpanId) {
-    Map<String, String> headers = new HashMap<>();
-    headers.put(TRACE_ID_KEY.toUpperCase(), traceId);
-    headers.put(SPAN_ID_KEY.toUpperCase(), spanId);
+    // spotless:off
+    Map<String, String> headers = headers(
+        TRACE_ID_KEY, traceId,
+        SPAN_ID_KEY, spanId
+    );
+    // spotless:on
 
     TagContext context = this.extractor.extract(headers, stringValuesMap());
 
@@ -224,11 +234,14 @@ void extractHeaderTagsWithNoPropagation() {
   @Test
   void extractHeadersWithForwarding() {
     String forwarded = "for=" + FORWARDED_IP + ":" + FORWARDED_PORT;
-    Map<String, String> tagOnlyCtx = singletonMap("Forwarded", forwarded);
-    Map<String, String> fullCtx = new HashMap<>();
-    fullCtx.put(TRACE_ID_KEY.toUpperCase(), "1");
-    fullCtx.put(SPAN_ID_KEY.toUpperCase(), "2");
-    fullCtx.put("Forwarded", forwarded);
+    Map<String, String> tagOnlyCtx = headers("Forwarded", forwarded);
+    // spotless:off
+    Map<String, String> fullCtx = headers(
+        TRACE_ID_KEY, "1",
+        SPAN_ID_KEY, "2",
+        "Forwarded", forwarded
+    );
+    // spotless:on
 
     TagContext context = extractor.extract(tagOnlyCtx, stringValuesMap());
 
@@ -246,14 +259,18 @@ void extractHeadersWithForwarding() {
 
   @Test
   void extractHeadersWithXForwarding() {
-    Map<String, String> tagOnlyCtx = new HashMap<>();
-    tagOnlyCtx.put("X-Forwarded-For", FORWARDED_IP);
-    tagOnlyCtx.put("X-Forwarded-Port", FORWARDED_PORT);
-    Map<String, String> fullCtx = new HashMap<>();
-    fullCtx.put(TRACE_ID_KEY.toUpperCase(), "1");
-    fullCtx.put(SPAN_ID_KEY.toUpperCase(), "2");
-    fullCtx.put("x-forwarded-for", FORWARDED_IP);
-    fullCtx.put("x-forwarded-port", FORWARDED_PORT);
+    // spotless:off
+    Map<String, String> tagOnlyCtx = headers(
+        "X-Forwarded-For", FORWARDED_IP,
+        "X-Forwarded-Port", FORWARDED_PORT
+    );
+    Map<String, String> fullCtx = headers(
+        TRACE_ID_KEY, "1",
+        SPAN_ID_KEY, "2",
+        "x-forwarded-for", FORWARDED_IP,
+        "x-forwarded-port", FORWARDED_PORT
+    );
+    // spotless:on
 
     TagContext context = extractor.extract(tagOnlyCtx, stringValuesMap());
 
@@ -272,16 +289,18 @@ void extractHeadersWithXForwarding() {
 
   @Test
   void extractEmptyHeadersReturnsNull() {
-    assertNull(
-        extractor.extract(singletonMap("ignored-header", "ignored-value"), stringValuesMap()));
+    assertNull(extractor.extract(headers("ignored-header", "ignored-value"), stringValuesMap()));
   }
 
   @Test
   void extractHttpHeadersWithInvalidNonNumericId() {
-    Map<String, String> headers = new HashMap<>();
-    headers.put(TRACE_ID_KEY.toUpperCase(), "traceId");
-    headers.put(SPAN_ID_KEY.toUpperCase(), "spanId");
-    headers.put(SOME_HEADER, SOME_VALUE);
+    // spotless:off
+    Map<String, String> headers = headers(
+        TRACE_ID_KEY, "traceId",
+        SPAN_ID_KEY, "spanId",
+        SOME_HEADER, SOME_VALUE
+    );
+    // spotless:on
 
     TagContext context = extractor.extract(headers, stringValuesMap());
 
@@ -291,10 +310,13 @@ void extractHttpHeadersWithInvalidNonNumericId() {
 
   @Test
   void extractHttpHeadersWithOutOfRangeSpanId() {
-    Map<String, String> headers = new HashMap<>();
-    headers.put(TRACE_ID_KEY.toUpperCase(), "0");
-    headers.put(SPAN_ID_KEY.toUpperCase(), "-1");
-    headers.put(SOME_HEADER, SOME_VALUE);
+    // spotless:off
+    Map<String, String> headers = headers(
+        TRACE_ID_KEY, "0",
+        SPAN_ID_KEY, "-1",
+        SOME_HEADER, SOME_VALUE
+    );
+    // spotless:on
 
     TagContext context = extractor.extract(headers, stringValuesMap());
 
@@ -314,9 +336,12 @@ void extractHttpHeadersWithOutOfRangeSpanId() {
   })
   void extractIdsWhileRetainingTheOriginalString(
       String traceId, String spanId, long expectedSpanId) {
-    Map<String, String> headers = new HashMap<>();
-    headers.put(TRACE_ID_KEY.toUpperCase(), traceId);
-    headers.put(SPAN_ID_KEY.toUpperCase(), spanId);
+    // spotless:off
+    Map<String, String> headers = headers(
+        TRACE_ID_KEY, traceId,
+        SPAN_ID_KEY, spanId
+    );
+    // spotless:on
     B3TraceId expectedTraceId = B3TraceId.fromHex(traceId);
 
     ExtractedContext context = (ExtractedContext) extractor.extract(headers, stringValuesMap());
@@ -341,17 +366,20 @@ private static String trimmed(String hex) {
 
   @Test
   void extractCommonHttpHeaders() {
-    Map<String, String> headers = new HashMap<>();
-    headers.put(HttpCodec.USER_AGENT_KEY, "some-user-agent");
-    headers.put(HttpCodec.X_CLUSTER_CLIENT_IP_KEY, "1.1.1.1");
-    headers.put(HttpCodec.X_REAL_IP_KEY, "2.2.2.2");
-    headers.put(HttpCodec.X_CLIENT_IP_KEY, "3.3.3.3");
-    headers.put(HttpCodec.TRUE_CLIENT_IP_KEY, "4.4.4.4");
-    headers.put(HttpCodec.FORWARDED_FOR_KEY, "5.5.5.5");
-    headers.put(HttpCodec.FORWARDED_KEY, "6.6.6.6");
-    headers.put(HttpCodec.FASTLY_CLIENT_IP_KEY, "7.7.7.7");
-    headers.put(HttpCodec.CF_CONNECTING_IP_KEY, "8.8.8.8");
-    headers.put(HttpCodec.CF_CONNECTING_IP_V6_KEY, "9.9.9.9");
+    // spotless:off
+    Map<String, String> headers = headers(
+        HttpCodec.USER_AGENT_KEY, "some-user-agent",
+        HttpCodec.X_CLUSTER_CLIENT_IP_KEY, "1.1.1.1",
+        HttpCodec.X_REAL_IP_KEY, "2.2.2.2",
+        HttpCodec.X_CLIENT_IP_KEY, "3.3.3.3",
+        HttpCodec.TRUE_CLIENT_IP_KEY, "4.4.4.4",
+        HttpCodec.FORWARDED_FOR_KEY, "5.5.5.5",
+        HttpCodec.FORWARDED_KEY, "6.6.6.6",
+        HttpCodec.FASTLY_CLIENT_IP_KEY, "7.7.7.7",
+        HttpCodec.CF_CONNECTING_IP_KEY, "8.8.8.8",
+        HttpCodec.CF_CONNECTING_IP_V6_KEY, "9.9.9.9"
+    );
+    // spotless:on
 
     TagContext context = extractor.extract(headers, stringValuesMap());
 

@@ -1,11 +1,15 @@
 package datadog.trace.core.propagation;
 
+import static datadog.trace.api.ConfigDefaults.DEFAULT_PROPAGATION_B3_PADDING_ENABLED;
 import static datadog.trace.api.sampling.PrioritySampling.UNSET;
 import static datadog.trace.bootstrap.instrumentation.api.ContextVisitors.stringValuesMap;
 import static datadog.trace.core.propagation.B3HttpCodec.B3_KEY;
 import static datadog.trace.core.propagation.B3HttpCodec.SAMPLING_PRIORITY_KEY;
 import static datadog.trace.core.propagation.B3HttpCodec.SPAN_ID_KEY;
 import static datadog.trace.core.propagation.B3HttpCodec.TRACE_ID_KEY;
+import static datadog.trace.core.propagation.B3TestHelper.spanIdOrPadded;
+import static datadog.trace.core.propagation.B3TestHelper.traceIdOrPadded;
+import static datadog.trace.core.propagation.B3TestHelper.trimHex;
 import static java.util.Collections.emptyMap;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
@@ -28,15 +32,17 @@
 import org.junit.jupiter.params.converter.ConvertWith;
 import org.tabletest.junit.TableTest;
 
-abstract class B3HttpInjectorTest extends DDCoreJavaSpecification {
+class B3HttpInjectorTest extends DDCoreJavaSpecification {
 
   private static final CarrierSetter<Map<String, String>> MAP_SETTER = Map::put;
 
   private HttpCodec.Injector injector;
   private HttpCodec.Extractor extractor;
   private CoreTracer tracer;
 
-  protected abstract boolean tracePropagationB3Padding();
+  protected boolean tracePropagationB3Padding() {
+    return DEFAULT_PROPAGATION_B3_PADDING_ENABLED;
+  }
 
   @BeforeEach
   void setup() {
@@ -77,8 +83,8 @@ void injectHttpHeaders(
     Map<String, String> carrier = new HashMap<>();
     this.injector.inject(spanContext, carrier, MAP_SETTER);
 
-    String traceIdHex = idOrPadded(traceId, 32);
-    String spanIdHex = idOrPadded(spanId, 16);
+    String traceIdHex = traceIdOrPadded(traceId, tracePropagationB3Padding());
+    String spanIdHex = spanIdOrPadded(spanId, tracePropagationB3Padding());
     assertEquals(traceIdHex, carrier.get(TRACE_ID_KEY));
     assertEquals(spanIdHex, carrier.get(SPAN_ID_KEY));
 
@@ -113,51 +119,14 @@ void injectHttpHeadersWithExtractedOriginal(String traceId, String spanId) {
     Map<String, String> carrier = new HashMap<>();
     this.injector.inject(mockedContext, carrier, MAP_SETTER);
 
-    String traceIdHex = idOrPadded(traceId, 32);
-    String spanIdHex = idOrPadded(trimHex(spanId), 16);
+    String traceIdHex = traceIdOrPadded(traceId, tracePropagationB3Padding());
+    String spanIdHex = spanIdOrPadded(trimHex(spanId), tracePropagationB3Padding());
     assertEquals(traceIdHex, carrier.get(TRACE_ID_KEY));
     assertEquals(spanIdHex, carrier.get(SPAN_ID_KEY));
     assertEquals(traceIdHex + "-" + spanIdHex, carrier.get(B3_KEY));
     assertEquals(3, carrier.size());
   }
 
-  private String idOrPadded(long id, int size) {
-    return idOrPadded(Long.toHexString(id), size);
-  }
-
-  private String idOrPadded(String id, int size) {
-    if (!tracePropagationB3Padding()) {
-      return id.toLowerCase();
-    }
-    return padHexLower(id, size);
-  }
-
-  private static String padHexLower(String hex, int size) {
-    String lower = hex.toLowerCase();
-    int diff = size - lower.length();
-    if (diff <= 0) {
-      return lower;
-    }
-    StringBuilder sb = new StringBuilder(size);
-    for (int i = 0; i < diff; i++) {
-      sb.append('0');
-    }
-    sb.append(lower);
-    return sb.toString();
-  }
-
-  private static String trimHex(String hex) {
-    int length = hex.length();
-    int firstNonZero = 0;
-    while (firstNonZero < length && hex.charAt(firstNonZero) == '0') {
-      firstNonZero++;
-    }
-    if (firstNonZero == length) {
-      return "0";
-    }
-    return hex.substring(firstNonZero, length);
-  }
-
   private DDSpanContext mockedSpanContext(TagContext context) {
     return mockedSpanContext(context.getTraceId(), context.getSpanId(), UNSET);
   }
@@ -194,11 +163,4 @@ protected boolean tracePropagationB3Padding() {
       return false;
     }
   }
-
-  static class B3HttpInjectorPaddedTest extends B3HttpInjectorTest {
-    @Override
-    protected boolean tracePropagationB3Padding() {
-      return true;
-    }
-  }
 }