Extract a string constant into a final field.

PiperOrigin-RevId: 166329484
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaCommon.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaCommon.java
index 79475b2..3490db7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaCommon.java
@@ -86,7 +86,8 @@
             ActionAnalysisMetadata action = analysisEnvironment.getLocalGeneratingAction(artifact);
             if (action instanceof JavaCompileAction) {
               addOutputs(metadataFilesBuilder, action, JavaSemantics.COVERAGE_METADATA);
-            } else if (action != null && action.getMnemonic().equals("JavaResourceJar")) {
+            } else if (action != null
+                && action.getMnemonic().equals(ResourceJarActionBuilder.MNEMONIC)) {
               // recurse on resource jar actions
               collectMetadataArtifacts(
                   action.getInputs(), analysisEnvironment, metadataFilesBuilder);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/ResourceJarActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/java/ResourceJarActionBuilder.java
index af7d596..0d9cf42 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/ResourceJarActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/ResourceJarActionBuilder.java
@@ -35,6 +35,8 @@
 
 /** Builds the action to package the resources for a Java rule into a jar. */
 public class ResourceJarActionBuilder {
+  public static final String MNEMONIC = "JavaResourceJar";
+
   private Artifact outputJar;
   private Map<PathFragment, Artifact> resources = ImmutableMap.of();
   private NestedSet<Artifact> resourceJars = NestedSetBuilder.emptySet(Order.STABLE_ORDER);
@@ -141,7 +143,7 @@
             .addInputs(classpathResources)
             .setCommandLine(command.build())
             .setProgressMessage("Building Java resource jar")
-            .setMnemonic("JavaResourceJar")
+            .setMnemonic(MNEMONIC)
             .build(ruleContext));
   }