fix FinalizerNullsFields not checking method signature (spotbugs#3210)

CHANGELOG.md

@@ -33,6 +33,7 @@ Currently the versioning policy of this project follows [Semantic Versioning v2.
 - Added missing comma between line number and confidence when describing matching and mismatching bugs for tests ([#3187](https://github.com/spotbugs/spotbugs/pull/3187))
 - Fixed method matchers with array types ([#3203](https://github.com/spotbugs/spotbugs/issues/3203))
 - Fix SARIF report's message property in Exception to meet the standard ([#3197](https://github.com/spotbugs/spotbugs/issues/3197))
+- Fixed `FI_FINALIZER_NULLS_FIELDS` FPs for functions called finalize() but not with the correct signature. ([#3207](https://github.com/spotbugs/spotbugs/issues/3207))
 
 ### Cleanup
 - Cleanup thread issue and regex issue in test-harness ([#3130](https://github.com/spotbugs/spotbugs/issues/3130))

spotbugs/src/main/java/edu/umd/cs/findbugs/detect/FinalizerNullsFields.java

@@ -24,7 +24,6 @@
 
 import org.apache.bcel.Const;
 import org.apache.bcel.classfile.Code;
-import org.apache.bcel.classfile.Field;
 import org.apache.bcel.classfile.Method;
 
 import edu.umd.cs.findbugs.BugAccumulator;
@@ -53,16 +52,7 @@ public FinalizerNullsFields(BugReporter bugReporter) {
 
     @Override
     public void visit(Method obj) {
-        if ("finalize".equals(obj.getName())) {
-            inFinalize = true;
-        } else {
-            inFinalize = false;
-        }
-    }
-
-    @Override
-    public void visit(Field obj) {
-
+        inFinalize = "finalize".equals(obj.getName()) && "()V".equals(obj.getSignature());
     }
 
     @Override