Fix some method references

build.gradle

@@ -29,13 +29,21 @@ buildscript {
         classpath 'com.palantir.gradle.gitversion:gradle-git-version:0.11.0'
         classpath 'com.palantir.gradle.consistentversions:gradle-consistent-versions:1.11.2'
         classpath "me.champeau.gradle:jmh-gradle-plugin:0.4.7"
+
+        // just until baseline upgrades
+        classpath 'com.diffplug.spotless:spotless-plugin-gradle:3.24.2'
     }
 }
 
 apply plugin: 'com.palantir.git-version'
 apply plugin: 'com.palantir.baseline'
 apply plugin: 'com.palantir.consistent-versions'
 
+repositories {
+    jcenter()
+    maven { url "http://palantir.bintray.com/releases" }
+}
+
 allprojects {
     version gitVersion()
     group 'com.palantir.tracing'

tracing/src/test/java/com/palantir/tracing/DeferredTracerTest.java

@@ -44,7 +44,7 @@ public void testIsSerializable() throws IOException, ClassNotFoundException {
         try (ObjectInputStream objectInputStream = new ObjectInputStream(bais)) {
             DeferredTracer deserialized = (DeferredTracer) objectInputStream.readObject();
 
-            String trace = deserialized.withTrace(() -> Tracer.getTraceId());
+            String trace = deserialized.withTrace(Tracer::getTraceId);
             assertThat(trace).isEqualTo("defaultTraceId");
         }
     }

tracing/src/test/java/com/palantir/tracing/TracersTest.java

@@ -258,9 +258,7 @@ public void testWrapRunnable_startsNewSpan() throws Exception {
     public void testWrapCallableWithNewTrace_traceStateInsideCallableIsIsolated() throws Exception {
         String traceIdBeforeConstruction = Tracer.getTraceId();
 
-        Callable<String> wrappedCallable = Tracers.wrapWithNewTrace(() -> {
-            return Tracer.getTraceId();
-        });
+        Callable<String> wrappedCallable = Tracers.wrapWithNewTrace(Tracer::getTraceId);
 
         String traceIdFirstCall = wrappedCallable.call();
         String traceIdSecondCall = wrappedCallable.call();
@@ -282,9 +280,7 @@ public void testWrapCallableWithNewTrace_traceStateInsideCallableIsIsolated() th
 
     @Test
     public void testWrapCallableWithNewTrace_traceStateInsideCallableHasSpan() throws Exception {
-        Callable<List<OpenSpan>> wrappedCallable = Tracers.wrapWithNewTrace(() -> {
-            return getCurrentTrace();
-        });
+        Callable<List<OpenSpan>> wrappedCallable = Tracers.wrapWithNewTrace(TracersTest::getCurrentTrace);
 
         List<OpenSpan> spans = wrappedCallable.call();
 
@@ -298,9 +294,7 @@ public void testWrapCallableWithNewTrace_traceStateInsideCallableHasSpan() throw
 
     @Test
     public void testWrapCallableWithNewTrace_traceStateInsideCallableHasGivenSpan() throws Exception {
-        Callable<List<OpenSpan>> wrappedCallable = Tracers.wrapWithNewTrace("operation", () -> {
-            return getCurrentTrace();
-        });
+        Callable<List<OpenSpan>> wrappedCallable = Tracers.wrapWithNewTrace("operation", TracersTest::getCurrentTrace);
 
         List<OpenSpan> spans = wrappedCallable.call();
 
@@ -335,9 +329,7 @@ public void testWrapCallableWithNewTrace_traceStateRestoredToCleared() throws Ex
 
     @Test
     public void testWrapCallableWithNewTrace_canSpecifyObservability() throws Exception {
-        Callable<Boolean> rawCallable = () -> {
-            return Tracer.copyTrace().get().isObservable();
-        };
+        Callable<Boolean> rawCallable = () -> Tracer.copyTrace().get().isObservable();
 
         Callable<Boolean> sampledCallable = Tracers.wrapWithNewTrace("someTraceId", Observability.SAMPLE, rawCallable);
         Callable<Boolean> unSampledCallable = Tracers.wrapWithNewTrace("someTraceId", Observability.DO_NOT_SAMPLE,