Delay initializing the CacheBuilder logger until it is needed.

This is progress toward addressing the Java agent / `premain` problem discussed in #6566.

(And we're careful to avoid lambdas and method references so as to avoid #6565.)

RELNOTES=Fixed some problems with [using Guava from a Java Agent](#6566). (But we don't test that configuration, and we don't know how well we'll be able to keep it working.)
PiperOrigin-RevId: 542247494

android/guava/src/com/google/common/cache/CacheBuilder.java

@@ -271,7 +271,10 @@ public long read() {
         }
       };
 
-  private static final Logger logger = Logger.getLogger(CacheBuilder.class.getName());
+  // We use a holder class to delay initialization: https://github.com/google/guava/issues/6566
+  private static final class LoggerHolder {
+    static final Logger logger = Logger.getLogger(CacheBuilder.class.getName());
+  }
 
   static final int UNSET_INT = -1;
 
@@ -950,7 +953,8 @@ private void checkWeightWithWeigher() {
         checkState(maximumWeight != UNSET_INT, "weigher requires maximumWeight");
       } else {
         if (maximumWeight == UNSET_INT) {
-          logger.log(Level.WARNING, "ignoring weigher specified without maximumWeight");
+          LoggerHolder.logger.log(
+              Level.WARNING, "ignoring weigher specified without maximumWeight");
         }
       }
     }

guava/src/com/google/common/cache/CacheBuilder.java

@@ -272,7 +272,10 @@ public long read() {
         }
       };
 
-  private static final Logger logger = Logger.getLogger(CacheBuilder.class.getName());
+  // We use a holder class to delay initialization: https://github.com/google/guava/issues/6566
+  private static final class LoggerHolder {
+    static final Logger logger = Logger.getLogger(CacheBuilder.class.getName());
+  }
 
   static final int UNSET_INT = -1;
 
@@ -1056,7 +1059,8 @@ private void checkWeightWithWeigher() {
         checkState(maximumWeight != UNSET_INT, "weigher requires maximumWeight");
       } else {
         if (maximumWeight == UNSET_INT) {
-          logger.log(Level.WARNING, "ignoring weigher specified without maximumWeight");
+          LoggerHolder.logger.log(
+              Level.WARNING, "ignoring weigher specified without maximumWeight");
         }
       }
     }