[ErrorProne] Fix UnnecessaryMethodReference Check Findings (#37785)

Author: stankiewicz

buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy

@@ -1557,7 +1557,6 @@ class BeamModulePlugin implements Plugin<Project> {
             "TimeUnitConversionChecker",
             "UndefinedEquals",
             "UnescapedEntity",
-            "UnnecessaryMethodReference",
             "UnnecessaryParentheses",
             "UnrecognisedJavadocTag",
             // errorprone 3.2.0+ checks

sdks/java/core/src/test/java/org/apache/beam/sdk/io/TextIOWriteTest.java

@@ -319,21 +319,21 @@ public void testDynamicDefaultFilenamePolicy() throws Exception {
 
     Iterable<String> aElements =
         elements.stream()
-            .filter(Predicates.compose(new StartsWith("a"), new ExtractWriteDestination())::apply)
+            .filter(Predicates.compose(new StartsWith("a"), new ExtractWriteDestination()))
             .collect(Collectors.toList())
             .stream()
             .map(Functions.toStringFunction())
             .collect(Collectors.toList());
     Iterable<String> bElements =
         elements.stream()
-            .filter(Predicates.compose(new StartsWith("b"), new ExtractWriteDestination())::apply)
+            .filter(Predicates.compose(new StartsWith("b"), new ExtractWriteDestination()))
             .collect(Collectors.toList())
             .stream()
             .map(Functions.toStringFunction())
             .collect(Collectors.toList());
     Iterable<String> cElements =
         elements.stream()
-            .filter(Predicates.compose(new StartsWith("c"), new ExtractWriteDestination())::apply)
+            .filter(Predicates.compose(new StartsWith("c"), new ExtractWriteDestination()))
             .collect(Collectors.toList())
             .stream()
             .map(Functions.toStringFunction())

sdks/java/harness/src/main/java/org/apache/beam/fn/harness/CombineRunners.java

@@ -123,11 +123,11 @@ void startBundle() {
     }
 
     void processElement(WindowedValue<KV<KeyT, InputT>> elem) throws Exception {
-      getGroupingTable().put(elem, output::accept);
+      getGroupingTable().put(elem, output);
     }
 
     void finishBundle() throws Exception {
-      getGroupingTable().flush(output::accept);
+      getGroupingTable().flush(output);
       groupingTable = null;
     }
   }