diff --git a/build.gradle b/build.gradle
index ac9eb4948..9fb75df86 100644
--- a/build.gradle
+++ b/build.gradle
@@ -65,7 +65,7 @@ allprojects {
             ]
 
             options.errorprone {
-                option('NullAway:AnnotatedPackages', 'com.palantir')
+                option('NullAway:AnnotatedPackages', 'com.palantir,com.google.common')
                 option('NullAway:CheckOptionalEmptiness', 'true')
                 option('AllSuggestionsAsWarnings') // https://github.com/google/error-prone/pull/3301
 
diff --git a/changelog/@unreleased/pr-1570.v2.yml b/changelog/@unreleased/pr-1570.v2.yml
new file mode 100644
index 000000000..2ccee2cfb
--- /dev/null
+++ b/changelog/@unreleased/pr-1570.v2.yml
@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Enforce NullAway for Guava packages
+  links:
+  - https://github.com/palantir/tritium/pull/1570
diff --git a/tritium-processor/src/main/java/com/palantir/tritium/processor/Methods.java b/tritium-processor/src/main/java/com/palantir/tritium/processor/Methods.java
index 6df0d5004..0fdac164d 100644
--- a/tritium-processor/src/main/java/com/palantir/tritium/processor/Methods.java
+++ b/tritium-processor/src/main/java/com/palantir/tritium/processor/Methods.java
@@ -17,6 +17,7 @@
 package com.palantir.tritium.processor;
 
 import com.google.common.base.CaseFormat;
+import com.palantir.logsafe.Preconditions;
 import com.squareup.javapoet.CodeBlock;
 import com.squareup.javapoet.FieldSpec;
 import com.squareup.javapoet.TypeName;
@@ -66,9 +67,11 @@ static IdentityHashMap<MethodElements, String> methodStaticFieldName(
         IdentityHashMap<MethodElements, String> result = new IdentityHashMap<>();
         for (MethodElements method : instrumentedMethods) {
             String methodName = method.element().getSimpleName().toString();
-            String originalMethodFieldName = CaseFormat.LOWER_CAMEL
-                    .converterTo(CaseFormat.UPPER_UNDERSCORE)
-                    .convert(methodName);
+            String originalMethodFieldName = Preconditions.checkNotNull(
+                    CaseFormat.LOWER_CAMEL
+                            .converterTo(CaseFormat.UPPER_UNDERSCORE)
+                            .convert(methodName),
+                    "methodName cannot be null");
             String methodFieldName = originalMethodFieldName;
             for (int i = 1; true; i++) {
                 String finalName = methodFieldName;