Refactor not to use anon classes

Kotlin reflect doesn't like it

pmd-java/pom.xml

@@ -210,16 +210,6 @@
             <artifactId>guava</artifactId>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>org.jetbrains.kotlin</groupId>
-            <artifactId>kotlin-stdlib</artifactId>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.jetbrains.kotlin</groupId>
-            <artifactId>kotlin-test-junit</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.jetbrains</groupId>
             <artifactId>annotations</artifactId>

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/types/SentinelType.java

@@ -9,19 +9,36 @@ import java.util.Set;
 import java.util.function.Function;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import net.sourceforge.pmd.lang.java.symbols.JTypeDeclSymbol;
 
 /**
  * A "type" that exists outside of the main type hierarchy. This is only
  * used to have some sentinel values, to eg represent failure or errors.
  */
-class SentinelType implements JTypeMirror {
+final class SentinelType implements JTypeMirror {
 
     private final TypeSystem ts;
     private final String name;
+    private final JTypeDeclSymbol symbol;
 
     SentinelType(TypeSystem ts, String name) {
         this.ts = ts;
         this.name = name;
+        this.symbol = null;
+    }
+
+    SentinelType(TypeSystem ts, String name, JTypeDeclSymbol symbol) {
+        this.ts = ts;
+        this.name = name;
+        this.symbol = symbol;
+    }
+
+    @Nullable
+    @Override
+    public JTypeDeclSymbol getSymbol() {
+        return symbol;
     }
 
     @Override

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/types/TypeSystem.java

@@ -57,33 +57,7 @@ public final class TypeSystem {
      *
      * <p>This implementation uses this as the type of the 'null' literal.
      */
-    public final JTypeMirror NULL_TYPE = new JTypeMirror() {
-
-        @Override
-        public JTypeMirror subst(Function<? super SubstVar, ? extends @NonNull JTypeMirror> subst) {
-            return this;
-        }
-
-        @Override
-        public TypeSystem getTypeSystem() {
-            return TypeSystem.this;
-        }
-
-        @Override
-        public @Nullable JClassSymbol getSymbol() {
-            return null;
-        }
-
-        @Override
-        public <T, P> T acceptVisitor(JTypeVisitor<T, P> visitor, P p) {
-            return visitor.visitNullType(this, p);
-        }
-
-        @Override
-        public String toString() {
-            return "null";
-        }
-    };
+    public final JTypeMirror NULL_TYPE = new NullType();
 
 
     // primitives
@@ -203,21 +177,11 @@ public final class TypeSystem {
         primitivesByKind.put(PrimitiveTypeKind.DOUBLE, DOUBLE);
 
         JClassSymbol unresolvedTypeSym = symbolFactory.makeUnresolvedReference("/*unresolved*/", 0);
-        UNRESOLVED_TYPE = new SentinelType(this, "/*unresolved*/") {
-            @Override
-            public JTypeDeclSymbol getSymbol() {
-                return unresolvedTypeSym;
-            }
-        };
+        UNRESOLVED_TYPE = new SentinelType(this, "/*unresolved*/", unresolvedTypeSym);
 
         JClassSymbol primitiveVoidSym = ReflectedSymbols.getClassSymbol(symbolFactory, void.class);
         assert primitiveVoidSym != null : "void";
-        NO_TYPE = new SentinelType(this, "void") {
-            @Override
-            public JTypeDeclSymbol getSymbol() {
-                return primitiveVoidSym;
-            }
-        };
+        NO_TYPE = new SentinelType(this, "void", primitiveVoidSym);
 
         // reuse instances for common types
 
@@ -736,4 +700,31 @@ public final class TypeSystem {
         return new TypeVarImpl(this, symbol);
     }
 
+    private class NullType implements JTypeMirror {
+
+        @Override
+        public JTypeMirror subst(Function<? super SubstVar, ? extends @NonNull JTypeMirror> subst) {
+            return this;
+        }
+
+        @Override
+        public TypeSystem getTypeSystem() {
+            return TypeSystem.this;
+        }
+
+        @Override
+        public @Nullable JClassSymbol getSymbol() {
+            return null;
+        }
+
+        @Override
+        public <T, P> T acceptVisitor(JTypeVisitor<T, P> visitor, P p) {
+            return visitor.visitNullType(this, p);
+        }
+
+        @Override
+        public String toString() {
+            return "null";
+        }
+    }
 }

pmd-lang-test/pom.xml

@@ -121,6 +121,12 @@
             <scope>compile</scope>
         </dependency>
 
+        <dependency>
+            <groupId>io.kotest</groupId>
+            <artifactId>kotest-runner-console-jvm</artifactId>
+            <scope>compile</scope>
+        </dependency>
+
         <dependency>
             <groupId>org.jetbrains</groupId>
             <artifactId>annotations</artifactId>

pom.xml

@@ -847,6 +847,12 @@
                 <version>${kotest.version}</version>
                 <scope>test</scope>
             </dependency>
+            <dependency>
+                <groupId>io.kotest</groupId>
+                <artifactId>kotest-runner-console-jvm</artifactId>
+                <version>${kotest.version}</version>
+                <scope>test</scope>
+            </dependency>
             <dependency>
                 <groupId>io.kotest</groupId>
                 <artifactId>kotest-assertions-core-jvm</artifactId>