Add a lambda now that we can.

RELNOTES: None.
PiperOrigin-RevId: 160498120

src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java b/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java
index 19a9e43..d66a432 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java
@@ -852,23 +852,6 @@
 
   }
 
-  private static Function<String, String> sourceFunctionForMap(final Map<String, String> map) {
-    return new Function<String, String>() {
-      @Override
-      public String apply(String input) {
-        if (!map.containsKey(input)) {
-          return "default";
-        }
-
-        if (map.get(input).isEmpty()) {
-          return "command line";
-        }
-
-        return map.get(input);
-      }
-    };
-  }
-
   /**
    * Parses the command line arguments into a {@link OptionsParser} object.
    *
@@ -885,8 +868,19 @@
     OptionsParser parser = OptionsParser.newOptionsParser(optionClasses);
     parser.setAllowResidue(false);
     parser.parse(OptionPriority.COMMAND_LINE, null, args);
-    Function<? super String, String> sourceFunction =
-        sourceFunctionForMap(parser.getOptions(BlazeServerStartupOptions.class).optionSources);
+    Map<String, String> optionSources =
+        parser.getOptions(BlazeServerStartupOptions.class).optionSources;
+    Function<String, String> sourceFunction = option -> {
+      if (!optionSources.containsKey(option)) {
+        return "default";
+      }
+
+      if (optionSources.get(option).isEmpty()) {
+        return "command line";
+      }
+
+      return optionSources.get(option);
+    };
 
     // Then parse the command line again, this time with the correct option sources
     parser = OptionsParser.newOptionsParser(optionClasses);