use static block

Author: diegomarquezp

google-http-client-test/src/main/java/com/google/api/client/test/util/store/AbstractDataStoreFactoryTest.java

@@ -42,8 +42,13 @@
 @RunWith(JUnit4.class)
 public abstract class AbstractDataStoreFactoryTest {
 
-  private static final String STRING_ID = "String";
-  private static final String BOOLEAN_ID = "Boolean";
+  private static final String STRING_ID;
+  private static final String BOOLEAN_ID;
+
+  static {
+    STRING_ID = "String";
+    BOOLEAN_ID = "Boolean";
+  }
   DataStoreFactory dataStore;
   DataStore<String> stringTyped;
   DataStore<Boolean> boolTyped;